JPH0351828A - Composition of nonlinear optical material and production thereof - Google Patents

Abstract

PURPOSE:To obtain high stability and high nonlinear optical characteristics by comprising the above compsn. of >=2 kinds contg. at least one org. compd. of a pi electron conjugation type and at least one org. compd. which form a molecular salt structure. CONSTITUTION:Even the org. compd. of the pi electron conjugation type having an electron-donating group and electron-accepting group of which the independent crystals do not exhibit nonlinear optical activity as substituent can present the nonlinear optical activity of high efficiency when this compd. is mixed with a compd. having the molecular salt structure and is melted, then cooled to solidify. Namely, even the compd. which has the large super polarizability betaof the molecules but forms the crystal of central symmetry and, therefore, which alone has the nonlinear optical inertness can be changed to the structure in which the central symmetry does not exist by forming this compd. into the multi component system with the other compd. having the molecular salt structure. The nonlinear optical compsn. having the high stability and nonlinear optical characteristics is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention can be applied to various optical devices exhibiting nonlinear optical characteristics.Related to a nonlinear optical composition exhibiting high nonlinear optical characteristics and a method for producing the same.Conventional Technology Future Although there is a need for materials with large nonlinear optical properties and high-speed response as optical materials useful in optical devices, such materials include organic compounds with convergent π-electron systems rather than inorganic compound crystals in which lattice vibrations are involved. The general design guideline is to introduce strong donor substituents and acceptor substituents into molecules with π-electron conjugated systems. According to the method, although a single organic molecule has a very large hyperpolarizability due to the twin scratching moment induced inside the molecule, the molecules interact with other molecules and have central symmetry that cancels out each other. Even if a crystal is formed, there is a problem that, for example, SHG, which is a second-order nonlinear optical property, does not appear in such a centrosymmetric crystal.The present invention provides a nonlinear optical material with high stability and nonlinear optical properties. An object of the present invention is to provide a composition and a method for producing the same.A Means for Solving the Problem A composition of two or more types containing at least one π-electron conjugated organic compound, the composition comprising at least one of the organic compound. By using a nonlinear optical material composition in which a molecular salt structure is formed, a composition that does not have a centrosymmetric structure can be obtained, and high nonlinear optical properties can be achieved. The process of mixing and melting or mixing and dissolving two or more organic compounds containing at least one of the organic compounds forms a molecular salt structure. Even a π-electron conjugated organic compound having an electron-donating group and an electron-accepting group as substituents can exhibit highly efficient nonlinear optical activity by mixing and melting the compound with a compound having a molecular salt structure, cooling and solidifying the compound. This led to the present invention.
In order to form a centrosymmetric crystal, a compound that is nonlinearly optically inactive when used alone can be formed into a complex system with other compounds that have a molecular salt structure. In addition, the present inventors (Tomo) added at least two or more organic compounds, including a π-electron conjugated organic compound that does not exhibit nonlinear optical activity in a single crystal, to a molecular salt structure of either compound. It has also been found that it is possible to obtain a composite organic nonlinear material composition exhibiting highly efficient nonlinear optical activity by mixing, dissolving, and recrystallizing in a solvent that causes π electrons as referred to in the present invention. Aromatic ring compounds with donor and acceptor substituents in addition to nitroaniline compound derivatives such as varanitroaniline, etc. Conjugated olefinization of stilbene compound derivatives and benzalacetophenone derivatives Although Schiff base compounds having aromatic rings such as heterocyclic compounds such as benzoxadiazole derivatives and nitropyridine derivatives and aromatic rings such as benzylideneaniline derivatives are applicable to the present invention, specifically iLt, 4-substituted naphthalene derivatives, 4-dimethylamino-4 -Stilbene, 3-(4-methoxyphenyl)-1-(4-aminophenyl)-2-propen-1-one, chalcone derivative 4-nitro-7-chlorobenzoxadiazole 4° -nitrobenzylidene-3
-acetylamino-4-methoxyaniline, N-(4
-pyridinylmethylene)-4-dimethylaminobenzenamine dimethylsulfate, N-[2-(5-nitrobenzylidene)]-]4-methoxybenzenamine and similar compounds thereof are applicable to the present invention. As a donor substituent in
Optically active amine groups such as -Seliny/kL-tyrosinyl, alkoxy groups such as hydroxy, methoxy, ethoxy, n-butoxy, etc. (methyAt, ethyl)Lx, n-propy)
Lt, n-pliers) Lt, n-pliers) Lt,
A chain or branched alkyl group such as n-octadecyl, halogen, etc. may be mentioned.
Cyano isocyanato, formi/k Methyl carboxylate/k Alkoxycarbonyl such as ethyl carboxylate) l
< Sulfoni / 1 < Halogen etc. can be mentioned, but halogen 1 has properties of both donor and acceptor methods. Perchlorine, which is an acidic solvent that releases Alkaline aqueous solutions such as sodium oxide and potassium hydroxide, and mixed solvents of these and organic solvents are applicable.Also, the molecular salts of the present invention (hydrochloride, acetate, sulfonate, nitrate, phosphate, perchlorate) are applicable. Oxalates, methyl sulfates, iodine salts, iodates, borohydrofluorides, cinnamates, alkali metal salts, ammonium salts, etc. are applicable.The following is a detailed explanation of the present invention using Examples.Example 1 Varanitroaniline (hereinafter abbreviated as PNA, manufactured by Kanto Kagaku Co., Ltd.) and 4-nitrophenethylamine hydrochloride (hereinafter abbreviated as NPAHC, manufactured by Aldrich Co., Ltd.) were mixed in various molar ratios, and the molten liquid was cooled and solidified to obtain 9. Nd in the composition: YAG laser (1064
As shown in Figure 1, the SHG intensity was measured using the PNA molar ratio (PNA/NPAHC).
) is 0.6, SHG with very high efficiency (approximately 90 times that of urea) is observed. By cooling and solidifying, a new composition is formed, and it is thought that this composition has a structure that exhibits extremely high SHG efficiency, but the details of the structure of this composition are currently unknown. It is important that the dipole moments of each molecule do not cancel each other out.In other words, it may be considered to have a non-centrosymmetric structure, but two types of molecules may also form a complex or molecular compound, which does not have centrosymmetricity as a whole. Example 2 PNA and N-(P-nitrophenyl)ethylenediamine (NP E N) were mixed and dissolved in an acetic acid aqueous solution while heating, and recrystallized to produce an organic composite single-crystal material. The obtained single crystal material is irradiated with a Nd: YAG laser.The SHG intensity is measured.The SHG intensity depends on the concentration of the organic substance to be mixed and the concentration of the acetic acid aqueous solution.The SHG intensity is at least several times that of urea. Effects of the Invention Obtaining Strength The present invention (e) A nonlinear optical material composition comprising two or more types of compositions containing at least one π-electron conjugated organic compound, in which at least one of the organic compounds forms a molecular salt structure. Materials and methods for producing them Even if a material has a crystalline structure that is SHG-inactive when used alone, it is effective to obtain a material that exhibits high stability and high nonlinear optical properties by mixing it with an organic compound that has a molecular salt structure. Mu

[Brief explanation of drawings]

FIG. 1 is a diagram showing the composition dependence of the SHG intensity of the composition of Example 1.

Claims (4)

[Claims] (1) A nonlinear optical material composition consisting of two or more organic compounds including at least one π-electron conjugated organic compound, in which at least one of the organic compounds has a molecular salt structure. Characteristic nonlinear optical material composition. (2) One of the π-electron conjugated organic compounds has electron donating properties (
2. The nonlinear optical material composition according to claim 1, further comprising a substituent having donor properties and electron-withdrawing properties (acceptor properties). (3) A method for producing a composition in which two or more organic compounds containing at least one π-electron conjugated organic compound are melted or mixed and solidified by cooling, wherein at least one of the organic compounds is a molecular salt. A method for producing a nonlinear optical material composition characterized by having a structure. (4) A method for producing a nonlinear optical material composition characterized by mixing and dissolving two or more organic compounds containing at least one π-electron conjugated organic compound to form a molecular salt structure.