JPH0436731A - Novel aromatic nonlinear optical material - Google Patents

Abstract

PURPOSE:To utilize the above material as an optical bistable element and switching element by forming a solid soln. of various kinds of carboxylic acids contg. cyano groups and urea deriv. without having inversion symmetry. CONSTITUTION:This arom. org. nonlinear optical material consists of the solid soln. of the carboxylic acids expressed by general formula (I) and the urea deriv. In the formula (I), Ar denotes 5 to 14C arom. group. In the formula (I), X and Y are a hydrocarbon group. The substituents exclusive of a hydrogen atom exist preferably in a -CH=CH- group, p- position or o- position if either of X and Y is the hydrogen atom. The substituents exist preferably in p-position or o- position if both of X and Y are the exclusive of hydrogen atoms. This solid soln. is preferably formed of the carboxylic acids and the urea deriv. at 1:5 to 5:1 molar ratio. The resulted solid soln. has the form of a crystal, has excellent moldability, can be shaped to various kinds of elements and is applicable to a nonlinear optical application field.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to nonlinear optical materials, and more particularly to organic aromatic materials having large second-order nonlinear optical properties.

[Conventional technology]

A nonlinear optical effect is a nonlinear optical effect that, when a strong optical electric field such as that of a laser beam is applied to a material, the electric polarization response of the material is linearly proportional to the magnitude of the applied electric field. This refers to the appearance of higher-order effects than the following.

Secondary nonlinear optical effects include second harmonic generation, which converts the wavelength of incident light by half, parametric oscillation, which converts light of one type of wavelength into two types of light, and vice versa. There is secondary light mixing, which produces light of one type of wavelength from the light of . Due to these characteristics, materials with nonlinear optical effects will be used in the future as optical switches and optical memories used in optical data processing, information processing, or optical communication systems, or optical bistable devices used in optical signal processing. It may be used as an element such as an optical switch. Generally, in this field, LiNb0. Inorganic materials are mainly being researched and considered, but inorganic materials have a low figure of merit, a low response speed,
It has drawbacks such as poor formability, high hygroscopicity, and low stability, making it difficult to form a desired optical element.

In recent years, many attempts have been made to investigate organic materials in place of these inorganic materials.

This is because it has been confirmed and reported that the response of organic substances is mainly based on the polarization of the π-electron system, so the nonlinear optical effect is large and the response speed is also large. For example, AC3Symposium Series, Volume 233 (AC3Symposium 5eri
Many examples have been reported in ES Vol. 233, 1983).

The second-order nonlinear optical property that is the problem in the present invention is a third-order tensor, and therefore does not become apparent if a center of interest exists in a molecule or crystal. For this reason, even though organic substances have a large molecular nonlinear susceptibility at the molecular level, they become more susceptible to polarization during the solidification and crystallization stages due to the background polarization effect that causes the large nonlinear susceptibility to appear. There is a problem in that a stable centrally symmetrical structure is preferentially formed, and as a result, no second-order nonlinear optical effect is exhibited as an optical element.

In general, the second harmonic generation ability increases in long conjugated systems where the polarization within the molecule is large and the contribution of that polarization is large, but conversely, when the conjugation length becomes long, the absorption wavelength shifts to the longer wavelength side. , which corresponds to 1/2 wavelength of the incident light. At that time, the second harmonics generated may be absorbed, resulting in optical damage that changes the refractive index, chemical denaturation, or combustion due to absorption of thermal energy. Therefore, simply increasing the conjugate length is often not advantageous.

For example, compounds with increased molecular polarization by introducing groups with large electron-withdrawing properties such as carboxyl groups and cyano groups as shown in the following general formula (I), and various substituents into the benzene ring, , a large nonlinearity is expected as a result of the transfer effect of the electron configuration within the ring, but in reality, due to the magnitude of the molecular polarization, the structure has a center of inversion symmetry, and no second harmonic generation is observed. There are many things.

Generally, controlling crystal structure is a difficult technique, and it is particularly difficult to create a crystal system that breaks the center of symmetry.

In order to overcome this difficulty, the present inventor first applied for an invention utilizing an optically active chiral structure and filed a patent application on Patent Application No. 63-7.
Specification No. 2080, Specification of Japanese Patent Application No. 63720821)
, succeeded in directly expressing nonlinear susceptibility at the molecular level in the crystal structure.

Urea, which has a crystal structure with an asymmetric center, is a compound that generates second harmonics. However, as can be easily determined from its molecular structure, urea does not have a conjugated system, so it is essentially difficult to exhibit high nonlinear optical performance.

[Problem to be solved by the invention]

An object of the present invention is to provide a crystalline compound having no inversion symmetry and which has increased ability to generate second-order nonlinearity for various nonlinear optical elements.

[Means for Solving the Problems] The present invention has the following general formula (I) .
aromatic group, X and Y are the same or different, R,
A group represented by -0-, an amino group represented by N(Rz)Ri, -3R.

Group represented by, cyano group, nido tetra group, -COOR5, -
Ester group represented by 0COR, , CON (Rff
)R,, -N (R1) represents a functional group selected from the group consisting of an amide group represented by COR, , and a hydrocarbon group represented by -R1+, where R4 to RII are the same or different and represent carbon This is a novel aromatic nonlinear optical material characterized by being composed of a solid solution of a carboxylic acid represented by a number 1 to 8 hydrocarbon group or a hydrogen atom] and a urea derivative.

In general formula (I), Ar represents an aromatic group having 5 to 14 carbon atoms. Examples of this Ar include groups derived from pyridine, benzene, biphenyl, indene, naphthalene, biphenylene, acenaphthylene, fluorene, phenanthrene, anthracene, benzofuran, benzothiophene, indole, quinoline, isoquinoline, carbazole, and xanthine. . Among them,
Groups derived from benzene or naphthalene are preferred.

In addition, in the general formula (1), X and Y represent the aforementioned groups, such as alkoxy groups such as methoxy group, ethoxy group, n-propoxy group, and n-butoxy group; allyloxy groups such as phenoxy group; amino group; monomethylamino group,
Amino groups such as monoethylamino group, dimethylamino group, diethylamino group, di(n-propyl)amino group, methylethylamino group, anilino group, diphenylamino group;
Alkylthio groups such as methylthio group, ethylthio group, n-propylthio group, arylthio group such as phenylthio group; cyano group; nitro group; methyl ester group, ethyl ester group of carboxylic acid derived from aromatic group of Ar;
Ester groups represented by -COOR5 such as n-propyl ester group, n-butyl ester group, phenyl ester group; 10COR such as acetyloxy group, propionyloxy group, butyryloxy group, benzoyloxy group
, an amide group with ammonia of a carboxylic acid derived from an aromatic group of Ar, a methylamide group, an ethylamide group, a dimethylamide group, a diethylamide group, a propylamide group, a dipropylamide group, a butylamide group , dibutylamide group, anilide group, etc.
N (R7) Amide group represented by R8; -N (R1
)COR,. Amide group represented by; or methyl group,
Examples include hydrocarbon groups such as ethyl group, n-propyl group, n-butyl group, and n-pentyl group; preferred are alkoxy groups such as methoxy group, ethoxy group, and n-propoxy group; and aryloxy groups such as phenoxy group. groups; amino groups such as amino, monomethylamino, monoethylamino, dimethylamino, diethylamino, methylethylamino, anilino groups; alkylthio groups such as methylthio and ethylthio; arylthio groups such as phenylthio; Cyano group; methyl ester group, ethyl ester group of carboxylic acid derived from aromatic group of nitro group HAr,
Ester groups represented by -COOR, such as phenyl ester groups; acetyloxy groups, propionyloxy groups,
10 COR such as benzoyloxy group.

100N (R?) R1 such as ester group represented by, amide group with ammonia of carboxylic acid derived from aromatic group of Ar, methylamide group, ethylamide group, dimethylamide group, anilide group Amide group represented; -N (R,)COR, such as formylamide group, acetylamide group, benzoylamide group. An amide group represented by; or a hydrocarbon group such as a methyl group, an ethyl group, or an n-propyl group.

In addition, in general formula (1), when either X or Y is a hydrogen atom, the substituent other than the hydrogen atom is -CH=CH
It is preferably in the p-position or ○-position with the - group, and preferably in the p-position and ○-position when both are other than hydrogen atoms.

In order to have a high nonlinear optical effect, it is necessary to have a large dipole in the molecular structure, and for this purpose, general formula (1) has a cyano group and a carboxyl group present on the same carbon atom. let

In addition, it is desirable to have a conjugated system in order for the molecular polarizations to interfere with each other, but as the conjugation length increases, the absorption maximum extends toward longer wavelengths, causing damage due to the incident light wavelength or second harmonic. There is a possibility that this may occur. For this reason, the conjugate length must not be too long.

Examples of the carboxylic acid represented by the general formula (1) include the following compounds.

3-phenyl-2-cyanopropenoic acid, 3-(P-dimethylaminophenyl)-2-cyanopropenoic acid, 3
-(p-aminophenyl)-2cyanopropenoic acid, 3
-(p-diethylaminophenyl)-2-cyanopropenoic acid, 3-(p-dipropylaminophenyl)-2-
Cyanopropenoic acid, 3-(P-dibutylaminophenyl)-2-cyanopropenoic acid, 3-(p-monomethylaminophenyl)-2-cyanopropenoic acid, 3-(p-
3-(p-methoxyphenyl)-2-cyanopropenoic acid, 3-(p=ethoxyphenyl)-2 Cyanopropenoic acid, 3-(p-propyloxyphenyl)-2-cyanopropenoic acid, 3-(p-butyloxyphenyl)-
2-cyanopropenoic acid, 3-(p-pentyloxyphenyl)-2-cyanopropenoic acid, 3-(p-n-
hexyloxyphenyl)-2-cyanopropenoic acid,
3-(p-decaczydiphenyl)-2-cyanopropenoic acid and their m- and. -Substituted derivative; 3-(p-methylthiophenyl)-2-cyanopropenone'611.3-(p-ethylthiophenyl)2-cyanopropenoic acid, 3-(p-propylthiophenyl)-
2-cyanopropenoic acid, 3-(p-butylthiophenyl)-2-cyanopropenoic acid, 3-(p-n-pentylthiophenyl)-2-cyanopropenoic acid, 3-(p
-n-hexylthiophenyl)-2-cyanopropenoic acid, 3-(p-decanethiophenyl)-2-cyanopropenoic acid and their m- and o-3 substituted derivatives; 3-(p-cyanopropenoic acid) 3-(p-methyloxyphenyl) )-2-cyanopropenoic acid, 3-(p-ethyloxyphenyl)2-cyanopropenoic acid, 3-(p-propyloxyphenyl)-
2-cyanopropenoic acids and their m- and 0
-Substituted derivative; 3-(P-acetyloxyphenyl)-
2-cyanopropenoic acid, 3-(P-propionyloxyphenyl)-2-cyanopropenoic acid, 3-(p-butanoyloxyphenyl)-2-cyanopropenoic acid and m- and O-substitutions thereof Derivatives: 3-(p-nitrophenyl)-2-cyanopropenoic acid, 3-(m-nitrophenyl)-2-cyanopropenoic acid, 3-(o-nitrophenyl)-2-cyanopropenoic acid ; 3-(p-dimethylamidophenyl)-2-cyanopropenoic acid, 3-(p-diethylamidophenyl)-2-
Cyanopropenoic acid, 3-(p-dipropylamidophenyl)-2-cyanopropenoic acid, 3-(p-dibutylamidophenyl)-2cyanopropenoic acid and m- and O-substituted derivatives thereof; 3 -(p-acetylaminophenyl)-2-cyanopropenoic acid, 3-(p-propionylaminophenyl)
-2-cyanopropenoic acid and m- and O-substituted derivatives thereof; 3-(P-methylphenyl)-2-cyanopropenone M
,,3-(p-ethylphenyl)-2-cyanopropenoic acid, 3-(p-propylphenyl)2-cyanopropenoic acid, 3-(p-butylphenyl)-2-cyanopropenoic acid, 3 -(pn-pentylphenyl)-2-cyanopropenoic acid, 3-(pn-hexylphenyl)
Substituted phenyl-2-cyanopropenoic acid derivatives such as -2-cyanopropenoic acid, 3-(p-decamphenyl)2-cyanopropenoic acid and their m- and O-substituted derivatives: 2-cyano-5- phenyl-2,4-pentadienoic acid,
2-cyano-5-(p-dimethylaminophenyl)-2
, 4-pentadienoic acid, 2-cyano-5-(p-diethylaminophenyl)-2,4-pentadienoic acid, 2-cyano-5-(p-dipropylaminophenyl)-2,4-
Pentadienoic acid, 2-cyano-5-(p-dibutylaminophenyl)-2,4-pentadienoic acid, 2-cyano-
5-(P-monomethylaminophenyl)-2,4=pentadienoic acid, 2-cyano-5-(p-aminophenyl)
-2,4-pentadienoic acid and their m- and 0-substituted derivatives; 2-cyano-5-(p-methyloxyphenyl)-2,
4-Pentadienoic acid, 2-cyano-5-(p-ethyloxyphenyl)-2,4-pentadienoic acid, 2-cyano-5-(p-propyloxyphenyl)-2,4-pentadienoic acid, 2-cyano -5-(p-butyloxyphenyl)-2゜4-pentadienoic acid and their m-
h and 〇-substituted derivatives; 2-cyano-5-(p-methylthiophenyl)-2,4
-Pentadienoic acid, 2-cyano-5-(p-ethylthiophenyl)-2,4-pencudienoic acid, 2-cyano-5
-(p-propylthiophenyl)-2,4-pentadienoic acid, 2-cyano-5-(p-butylthiophenyl)-
2,4-pentadienoic acid and their m- and 0
-substituted derivatives; 2-cyano-5-(P-cyanophenyl)-2°4-pentadienoic acid and their m- and O-substituted derivatives; 2-cyano-5-(P-methyloxycarbonylphenyl)-2 , 4-pentadienoic acid, 2-cyano-5-(p
-ethyloxycarbonylphenyl)-2,4-pentadienoic acid, 2-cyano-5(p-7"ropyloxycarbonylphenyl)-2,4-pentadienoic acid, 2-cyano-5-(p-butyloxycarbonyl) phenyl)-2
, 4-pentadienoic acid and their m- and 0-
Substituted derivatives; 2-cyano-5-(p-nitrophenyl)-2,4-pentadienoic acid and m- and O-substituted derivatives thereof; 2-cyano-5-(p-dimethylamidophenyl)-2
, 4-pentadienoic acid, 2-cyano-5-(p-diethylamidophenyl)-2,4-pentadienoic acid, 2-cyano-5-(p-dipropylamidophenyl)-2,4
-Pentadienoic acid, 2cyano-5-(p-dibutylamidophenyl)-2,4-pentadienoic acid, 2-cyano-
5-(p-monomethylamidophenyl)-2,4-pentadienoic acid, 2-cyano-5-(p-amidophenyl)
-2,4-pentadienoic acid and m- and O-substituted derivatives thereof; 2-cyano-5-(p-acetylaminophenyl)-
2,4-pentadienoic acid, 2-cyano-5-(p-propionylaminophenyl)-2,4-pentadienoic acid and m- and 0-substituted derivatives thereof; 2-cyano-5-(p-methylphenyl) -2゜4-pentadienoic acid, 2-cyano-5-(p-ethylphenyl)-2,4-pentadienoic acid, 2-cyano-5-(p-
Substituted phenyl-2-cyano-2, such as propylphenyl)-2,4-pentadienoic acid, 2-cyano-5-(p-butylphenyl)-2,4-pentadienoic acid and m- and O-substituted derivatives thereof. ,4-pentadienoic acid derivatives: 2-cyano-7-phenyl-2,4,6-hebutatrienoic acid, 2-cyano-7-(P-dimethylaminophenyl)-2,4,6-hebutatrienoic acid, 2 -cyano-7-
(p-diethylaminophenyl)-2,4,6-hebutatrienoic acid, 2-cyano7-(p-dipropylaminophenyl)-2,4゜6-hebutatrienoic acid, 2-cyano-7-(p-dibutyl aminophenyl)-2,4,6-
Heptatrienoic acid, 2-cyano-7-(p-monomethylaminophenyl)-2,4,6-heptatrienoic acid, 2
-cyano-7-(p-monoethylaminophenyl)-2
,4,6-heptatrienoic acid and m- and 〇-substituted derivatives; 2-cyano-7-(p-methyloxyphenyl) 2.4
．． 6-heptatrienoic acid, 2-cyano-7-(p-ethyloxyphenyl)-2,4,6-heptatrienoic acid,
2-cyano-7-(P-propyloxyphenyl)-2
, 4,6-heptatrienoic acid, 2-cyano-7-(P-
butyloxyphenyl)-2,4,6-heptatrienoic acid and their m- and O-substituted derivatives; 2-cyano-7-(p-methylthiophenyl)-24,6-heptatrienoic acid, 2-cyano-7 -(p-ethylthiophenyl)-2,4,6-hebutatrienoic acid, 2-cyano-7-(p-propylthiophenyl)-2,4,6-hebutatrienoic acid, 2-cyano-7-( P-butylthiophenyl)-2,4,6-heptatrienoic acid and their m- and o-Wt substituted derivatives; 2-cyano-7-(p-cyanophenyl)-2°4.6
-heptatrienoic acid and m- and O-substituted derivatives thereof; 2-cyano-7-(P-methyloxycarbonylphenyl)-2,4,6-heptatrienoic acid, 2-cyano-7
-(p-ethyloxycarbonylphenyl)-2,4,
to 6-heptatrienoic acid, 2-cyano-7-(p-propyloxycarbonylphenyl)-2,4,6-heptatrienoic acid, 2-cyano-7-(p-butyloxycarbonylphenyl)-2,4,6- Butatrienoic acid and m- and O-substituted derivatives thereof; 2-cyano-7-(P-acetyloxyphenyl)-2
, 4,6-heptatrienoic acid, 2-cyano-7-(P-
2-cyano-7(P-butanoyloxyphenyl)-2,4,6-hebutatrienoic acid and m- and 0-substituted derivatives; -7-(p-dimethylamidophenyl)-2
, 4,6-hebutatrienoic acid, 2-cyano-7-(p-diethylamidophenyl)-2,4゜6-heptatrienoic acid, 2-cyano-7-(p-dipropylamidophenyl)
-2,4,6-heptatrienoic acid, 2-cyano-7-(
p-Dibutylamidophenyl)-2,4,6-hebutatrienoic acid, 2-cyano-7-(P-monomethylamidophenyl)-2,4,6-hebutatrienoic acid, 2-cyano-7-(p- 2-cyano-7-(p-nitrophenyl)-2゜4.6
-hebutatrienoic acids and their m- and 〇-
Substituted derivative; 2-cyano-7-(P-methylphenyl)-2゜46-
Hebutatrienoic acid, 2-cyano-7(p-ethylphenyl)-2,4,6-hebutatrienoic acid, 2-cyano-7
-(p-propylphenyl)-2,4,6-heptatrienoic acid, 2-cyano-7-(p-butylphenyl)-2
, 4,6-hebutatrienoic acid and their m- and O-substituted derivatives: 3-(3-indolyl)-2-cyanopropenoic acid,
3-(5-chloro-3-indolyl)-2cyanopropenoic acid, 2-cyano-5-(2-indolyl:l-2,
4-pentadienoic acid, 2-cyano-5-(3-indolyl)-2,4-pentadienoic acid 2-cyano-5-(5-
chloro-3-indolyl)-2,4-pentadienoic acid,
2-cyano-7-(3-indolyl)-2,4,6-heptatrienoic acid, 2-cyano-7-(2-indolyl)
2.4.6-Hebutatrienoic acid, 2-cyano7-(5-
Chloro-3-indolyl)-2,4゜6-heptatrienoic acid, 3-pyridine-2-cyanopropenoic acid, 5-pyridine-2-cyano-2゜4-pentadienoic acid, 7-pyridine-2-cyano- 2,46-heptatrienoic acid, 3
-carbazole-2-cyanopropenoic acid, 5-carbazole-2-cyano-2,4-pentadienoic acid, 7-carpab-2-cyano-2,4,6-hebutatrienoic acid.

Urea derivatives include urea, and at least one hydrogen of the amino group of urea is an alkyl group, a hydroxyalkyl group,
Refers to those asymmetrically substituted with haloalkyl groups, etc.

Preferred examples include urea, 1.1-dimethylurea, 1.1-diethylurea, 1.1-dimethylolurea, and ethylurea, which are commercially available as they are or recycled from a suitable solvent. It can be used after crystallization.

The solid solution of the present invention is preferably formed by the carboxylic acid represented by the general formula (I) and the urea derivative in a molar ratio of 1:5 to 5:1.

Formation of the solid solution can be carried out by mixing in the melt, solid phase or in a suitable solvent. Preferred examples of such solvents include alcohols such as ethanol and methanol, and cyclic ethers such as dioxane and tetrahydrofuran.

In addition, the method of forming a solid solution from the melt is more preferable from the viewpoint of operability, but from the viewpoint of stability of the compound, it is not preferable to perform the process at too high a temperature. It is desirable both from the viewpoint of safety and stability.

The thus obtained solid solution of a carboxylic acid and a urea derivative takes the form of a crystal, has excellent moldability, can be shaped into various devices, and can be applied to nonlinear optics applications.

〔Example〕

The present invention will be explained in more detail below using Examples. In addition, in the examples, unless otherwise specified, % is based on weight.

Furthermore, in the examples, the second harmonic generation was measured as follows.

i.e. nis, k, kuru (S, K).

Kurtz et al., Journal of Applied
Physics (J, App 1. Phys,) 39
Vol. 3798 (1968) on the powder of the invention. As the incident light source, a Nd:YAG laser (2KW/2Hz pulse) was used.
．． This was done by irradiating a powder sample filled in a glass cell with a light beam of 0.6 μm and detecting the green light generated.

Add 2.51 g of methyl cyanoacetate to a 40 m aqueous solution containing 1.72 g of sodium hydroxide, and then add p
-Add 2.76g of methoxycinnamaldehyde,
Heated to 5°C and continued stirring for 40 hours. After the reaction was completed, the solid was collected in addition to 12N hydrochloric acid.

This solid was recrystallized from a methanol/water mixed solvent to obtain the desired product 2.
．． 7g was obtained. The melting point of this product is 230°C. Elemental analysis values are: C: 68.00%, H: 4.90%, N: 5.
The calculated value is 99%, c: 68.10%, H: 4.8
5%, N: 6.11%, showing good agreement.

The absorption maximum wavelength in the ultraviolet-visible spectrum was 375 nm (in methanol solvent).

After 30.39 g of methyl cyanoacetate was dissolved in 12.77 g of a 40M aqueous solution of sodium hydroxide, 29.76 g of p-nitrobenzaldehyde was added under a nitrogen atmosphere, and stirring and heating under reflux were continued for 51 hours. After reaction, 12N
In addition to hydrochloric acid, the precipitate was collected. This solid was recrystallized twice from methanol to obtain crystals with a yield of 51%.

Melting point: 207°C1 Elemental analysis values: C: 55.91%, H
: 2.93%, N: 12.80%, and the calculated value of C:
55.02%, H: 2.75%, N: 12.84%, showing good agreement.

λ□ was 302 nm.

10 Golden Precepts Instead of 29.76g of P-nitrobenzaldehyde, 3
．． The reaction with methyl cyanoacetate was carried out in an aqueous sodium hydroxide solution in the same manner as in Reference Example 2, except that 25.38 g of 4-dimethoxybenzaldehyde was used, and the resulting solid was recrystallized twice from ethanol to obtain the desired product. 19.8
4g was obtained.

Melting point is 206.1°C1 Elemental analysis value is C: 61.94%
, Hl, 78%, N: 6.04%, and the calculated value of C:
61.79%, H: 4.76%, N: 6.01%, showing good agreement.

λ, □ were 353 n, m.

The infrared absorption spectrum contains C at a wave number of 2,221 cm-'.
N group, 1,596C'm-'1,573cm-'1
．． The presence of a benzene ring and a conjugated double bond was observed at 512 cm-'.

Various carboxylic acids shown in Table 1 [
Carboxylic acids (4 to 9)] (corresponding to Reference Examples 4 to 10, respectively) were synthesized.

(Left below) 1. Law A, 9
2.0 g of carboxylic acid (1) obtained in Reference Example 1 and 1.1
- 2.0 g of dimethyl urea was thoroughly mixed as a powder, heated and dissolved in 60 m of ethanol, and the homogeneous solution was cooled to room temperature to obtain 4.0 g of yellow crystals.

When this solid was pulverized and its ability to generate second harmonics was examined, it showed approximately three times the strength of urea.

2. Law B
! 2.0 g of carboxylic acid (1) obtained in Reference Example 1 and 1,
2.0 g of 1-dimethylurea was mixed well as a powder, and the mixture was left at 170'C for 20 minutes.

The mixed system became a homogeneous liquid, and when cooled to room temperature, a crystalline solid precipitated.

When this crystal was thoroughly crushed and its ability to generate second harmonics was examined, it showed an intensity approximately three times that of urea.

Formation method (A) of Example 1 of 3 to 11 or formation method of Example 2 (
In B), a solid solution of a carboxylic acid having the carboxylic acid number shown in Table 2 and a urea derivative was prepared, and its second harmonic (SHG) generation ability (ratio to urea) was investigated.

The results are shown in Table 2.

In Table 2, "c" in the urea derivative column stands for 1.1-dimethylurea, and rp stands for 1.1-dimethylurea. I-diethyl urea is
" indicates urea, and "molar ratio" indicates urea derivative/carvone.

Table 2 [Effects of the Invention] The non-inversion-symmetry solid solutions of various carboxylic acids containing cyano groups and urea derivatives of the present invention have a large nonlinear optical effect, so they can be used in optical data processing, information processing, or optical communication systems. It can be widely used as an element such as a switch, an optical bistable element used in optical signal calculation processing, or an optical switch.

Patent applicant Teijin Co., Ltd. Agent: Patent Attorney Takashi Shirai

Claims (1)

[Claims] (1) The following general formula (I) ▲Mathematical formulas, chemical formulas, tables, etc.▼・・・・・・(I) [In the formula, n represents 0, 1 or 2, and Ar represents carbon number 5 to 14.
aromatic group, X and Y are the same or different, R_
A group represented by 1-O-, an amino group represented by -N(R_2)R_3, -SR_4
A group represented by, a cyano group, a nitro group, -COOR_5,
Ester group represented by -OCOR_6, -CON(R_7)R_8, -N(R_9)COR_1
Represents a functional group selected from the group consisting of an amide group represented by _0 and a hydrocarbon group represented by -R_1_1, where R
_1 to R_1_1 are the same or different and represent a hydrocarbon group having 1 to 8 carbon atoms or a hydrogen atom] A novel aromatic nonlinear product characterized by being composed of a solid solution of a carboxylic acid represented by the following and a urea derivative. optical materials.