JPH0453712B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an optical recording material that is capable of multiplex recording with light of different wavelengths at the same location on the same material by utilizing the photochemical hole burning phenomenon. .

[Conventional technology] Photochemical hole burning is a photochemical hole burning method in which monochromatic light is irradiated onto a material that causes a photochemical reaction at an extremely low temperature, about the temperature of liquid helium, to selectively excite only molecules that absorb the light. It causes a reaction. At this time, holes with a sharp absorption spectrum of the material are formed, so recording becomes possible depending on the presence or absence of holes. moreover,
By sequentially changing the wavelength of the irradiated light, wavelength multiplexing recording can be performed at the same location on the same material. Using this method, it is possible to increase the recording density by about 1000 times compared to conventional optical digital recording media such as compact discs and laser discs.

Optical recording materials that use this PHB phenomenon are
It consists of a guest molecule, which is a photoreactive compound, and a host for dispersing it. In order to increase the wavelength multiplicity during optical recording, it is preferable to use an amorphous filter as a host in order to provide diversity in the dispersion state of the guest. For this purpose, polymers, silicate glass, and the like have conventionally been used as hosts. For example, there is a material in which the guest is tetraphenylporphin and the host is polymethyl methacrylate (Optics, 14 (4) 263-269), and a material in which the guest is quinizarine and the host is silicate glass (Journal of Applied Physics, 58). (9) 3559−
3565) are known.

[Problems to be solved by the present invention] However, the PHB phenomenon becomes unstable at temperatures higher than the liquid helium temperature, making it difficult to preserve records and
This has the disadvantage that reading becomes uncertain.
One reason for this is that irreversible structural changes are thermally induced in the PHB material, changing the microstructure around each guest molecule. Furthermore, in order to perform higher density recording than conventionally used materials, it is necessary to develop materials with even wider absorption bands.

The present invention aims to eliminate the drawbacks of the prior art, and by using an intercalation compound consisting of a cationic porphin derivative and a silicate layered body as a photoreactive component, it is more effective than the conventional porphin-based recording material. It is an object of the present invention to provide a wavelength multiplexing recording material that has good thermal stability and a wide absorption band.

[Means for Solving the Problem] The present invention has the following configuration to achieve the above object.

"An optical recording material characterized by being mainly composed of a silicate intercalation compound consisting of a porphine derivative having a cationic group and a silicate layered body." In the intercalation compound consisting of a porphine derivative and a silicate layered body, the cationic porphine derivative is firmly fixed by the layered anionic host, so it is presumed that irreversible structural changes upon temperature rise will be reduced. Ru. As a result, an increase in the half width of holes formed in the absorption spectrum of the material is suppressed, and the thermal stability of recording is improved.

A silicate layered body is generally composed of anionic silicate layers two-dimensionally bonded by covalent bonds and exchangeable cations between the layers. The bond between the silicate layer and the exchangeable cation is an ionic bond, which has a weaker bonding force than the covalent bond that forms the silicate layer. Therefore, the exchangeable cation can be exchanged with another metal cation or a cation of an organic compound without destroying the silicate layer. Therefore, in the present invention, a silicate intercalation compound is formed by exchanging it with a porphine derivative having a cationic group. The silicate layered material in the present invention may be any layered material having exchangeable cations between the layers. As such a silicate layered body, montmorillonite or saponite is most preferable because of its excellent transparency, and hectorite, vermiculite, baydate, and fluorohectolite can also be preferably used. Regarding the structure and composition of these layered materials, see “Intercalation Chemistry” by JMThomas.
Details are on pages 58-65.

Further, the porphine derivative may be any derivative having a cationic group, and examples of the cationic group include a quaternary amino group, a pyrrolidinium group, a morpholinium group, an N-alkylpyridinium group, and a pyridium group. It will be done. Among them, the following general formula [A] (In the formula, at least one selected from X ₁ , X ₂ , X ₃ , and X ₄ is an aryl group having a cationic group or a cationic heterocyclic group, and the others are hydrogen atoms or nonionic groups. ) is particularly preferred. This is because the cation moiety is separated from the conjugated system of the porphine by a benzene ring or the like that is not conjugated with the porphyne ring, so the cation moiety is less likely to affect the photochemical reactivity of the porphyne ring.

Examples of the nonionic group include phenyl group, methoxyphenyl group, nitrophenyl group, and alkyl group.

As the aryl group having a cationic group, a quaternary aminophenyl group is preferably used, and as the cationic heterocyclic group, an N-alkylpyridium group is preferably used. This is because the ionization state is stable without being affected by the hydrogen ion concentration of the silicate layered body.

Furthermore, from the viewpoint of forming a stable intercalation compound, 5, 10, 15,
20-tetra(4-N,N,N-trialkylaminophenyl)porphin or the following general formula [C]
5,10,15,20-tetra(4-N-alkylpyridinium)porphine represented by is particularly preferably used.

(However, in the formula, R ₁ to _{R 12} are alkyl groups having 1 to 6 carbon atoms.) (However, in the formula, R ₁₃ to _{R 16} are alkyl groups having 1 to 6 carbon atoms.) This has a substituent only at the para position of the benzene ring or pyridine ring, so it has a stable structure between planar layers. This is because it can be taken. In addition, R ₁ of general formula [B]
It is more preferable that the alkyl groups represented by ~R ₁₂ and R ₁₃ to _{R 16} in the general formula [C] are methyl groups. This is because the structure is the most compact, the degree of freedom of movement is small, and it is estimated that reversible changes are unlikely to occur at low temperatures.

5,10,15,20-tetra(4-N,N,N-trialkylaminophenyl)porphine is a 5,10,15,20-tetra(4-acetaminophenyl)porphine synthesized from acetaminobenzaldehyde and pyrrole. After hydrolyzing (enyl)porphine with an acid, it is reacted with a quaternizing agent such as an alkyl iodide to obtain a salt. Also, 5, 10, 15, 20-tetra (4-
N-alkylpyridinium) porphine is 5,
It is obtained as a salt by reacting 10,1520-tetra(4-pyridyl)porphine with a quaternizing agent such as an alkyl iodide.

The porphin silicate intercalation compound in the present invention is obtained by exchanging a cationic porphin derivative with sodium, calcium ion, etc., which are exchangeable cations between the layers of a silicate layered body, in water. The exchange rate of cations is preferably 0.1% to 50% in molar ratio of cations,
Furthermore, it is preferably 1% to 20%. This is because if the exchange rate is too high, the hole generation properties will deteriorate due to energy transfer between porphin molecules.
Furthermore, if the ratio is too low, the S/N during recording and reading becomes small.

Further, the optical recording material of the present invention can be used alone in the form of a film, but it may also be used after being dispersed in a polymer or the like.

[Examples] Hereinafter, the present invention will be described in more detail based on Examples, but the present invention is not limited thereto.

Example 1 Saponite dispersed in distilled water [compositional formula: Na _0.49
Mg _0.14 (Al _0.83 Mg _5.97 ) Si _7.20 O ₂₀ (OH) ₄ ] (manufactured by Kunimine Industries, trade name Smecton SA) 1 g contains tetra(4-N,N,N,-trimethylaminophenyl)
After adding 38 mg of porphyne tetra(p-toluenesulfonate) (manufactured by Dojindo Laboratories), washing with distilled water, A phenyl (porphin-saponite intercalation compound was obtained.
In line diffraction measurements, the interlayer distance of the raw material saponite is 12.61 Å (half width of (004) 1.91°), while the interlayer distance of this material is 12.52 Å ((004)
It was confirmed that an intercalation compound was formed because the sulfur contained in the counteranion of the raw material porphine was not detected in elemental analysis. This dispersion of intercalation compound was dried to form a cast film.

After cooling this film to liquid helium temperature,
Laser light with a wavelength of 666 nm and an intensity of 1 mw/cm ²
After irradiation for minutes, a hole with a half width of 0.4 cm ^-1 was formed. After this, the film is heated to a predetermined temperature,
The half width of the PHB ball was measured after cooling it to liquid helium temperature again.

Example 2 Saponite dispersed in distilled water [compositional formula: Na _0.49
Mg _0.14 (Al _0.83 Mg _5.97 ) Si _7.20 O ₂₀ (OH) ₄ ] (manufactured by Kunimine Industries, trade name Smecton SA) and 1 g of tetra(4-N-methylpyridinium) porphine tetraiodide (manufactured by Wako Pure Chemical Industries, Ltd.) After adding 30 mg, the mixture was washed with distilled water to obtain a tetra(4-N-methylpyridinium)porphine-saponite intercalation compound with a cation exchange rate of 10%. In X-ray diffraction measurement, the interlayer distance of the raw material saponite was 12.61.
Å (half width of (004) 1.91°), whereas
In this material, the interlayer distance changed to 13.00 Å (half width of (004) 2.46°), and elemental analysis did not detect iodine, which is the counter anion of the raw material porphyne. was confirmed to be formed. This intercalation compound was dispersed in polyvinyl alcohol to form a cast film.

After cooling this film to liquid helium temperature,
Laser light with a wavelength of 678 nm and an intensity of 1 mw/cm ² was irradiated for 5 minutes to form a ball with a half width of 1.1 cm ⁻¹ .
After this, the film was heated to a predetermined temperature, cooled again to liquid helium temperature, and the half-value width of the PHB hole was measured.

Comparative Example 1 After dissolving 10 g of isotactic polymethyl methacrylate (molecular weight = 400,000) in 120 ml of toluene, 0.05 g of tetraphenylporphine was added. By drying this solution in a shear dish, a film with a guest concentration of 10 ^-2 M and a thickness of 0.5 mm was prepared, which was used as a control sample. The film was cooled to liquid helium temperature and PHB holes were formed using laser light with a wavelength of 645 nm. The film was then heated to a predetermined temperature, cooled again to liquid helium temperature, and the half-width of the PHB holes was measured.

Figure 1 shows the PHB immediately after being irradiated with laser light.
The difference between the half-width ( ₀ ) of a hole and the half-width () after heating and recooling is illustrated as a function of the heating temperature. Tetra(4-N,N,N-
The case where the trimethylaminophenyl)porphine-saponite intercalation compound is used is ▲, the case where the tetra(4-N-methylpyridium)porphine-saponite intercalation compound of Example 2 is used is the case, and the tetra(4-N-methylpyridium)porphine-saponite intercalation compound of Comparative Example 1 is The case where a sample in which phenylporphine was dispersed in isotactic polymethyl methacrylate is shown by □. It can be seen that Examples 1 and 2 show less increase in the half width of the hole after heating and recooling, and are superior in thermal stability.

Furthermore, when comparing the half-width of the absorption band of the longest wavelength at which a hole should be formed, it is 26 nm and 25 nm in Examples 1 and 2, respectively;
In the case of Comparative Example 1, the wavelength range in which holes can be formed was 19 nm, but the wavelength range in which holes can be formed has increased, and high multiplexing is possible.

Example 3 Tetra (4
After adding 7 mg of -N-methylpyridinium) porphine tetraiodide (manufactured by Wako Pure Chemical Industries),
By washing with distilled water, a tetra(4-N-methylpyridium)porphine-montmorillonite intercalation compound with a cation exchange rate of 5% was obtained. In X-ray diffraction measurements, the interlayer distance of the raw material saponite was 12.5 Å.
On the other hand, in this material, the interlayer distance is
It was confirmed that an intercalation compound had been formed because the particle diameter had changed to 14.4 Å, and iodine, the counteranion of the raw material porphine, was not detected in elemental analysis. This intercalation compound was dispersed in polyvinyl alcohol to form a cast film. The half width of the absorption band at the longest wavelength of this film is 34 nm, which is increased compared to Comparative Example 1.

After cooling this to 4.2K, the wavelength is 680nm and the intensity is 1.
By irradiating with a laser beam of mw/cm ² for 5 minutes, a hole with a half width of 2.0 cm ⁻¹ was formed.

Example 4 Saponite dispersed in distilled water [compositional formula: Na _0.49
Mg _0.14 (Al _0.83 Mg _5.97 ) i _7.20 O ₂₀ (OH) ₄ ] (manufactured by Kunimine Industries, trade name Smecton SA) and 1 g of tetra(4-N-methylpyridinium) porphine tetraiodide (manufactured by Wako Pure Chemical Industries, Ltd.) After adding 60 mg, the mixture was washed with distilled water to obtain a tetra(4-N-methylpyridium)porphine-saponite intercalation compound with a cation exchange rate of 20%.

In X-ray diffraction measurements, the interlayer distance of the raw material saponite is 12.6 Å (half width of (004) 1.91°), whereas the interlayer distance of this material is 13.11 Å.
(half width of (004) 2.55°), and iodine, which is the counteranion of the raw material porphine, was not detected in elemental analysis.
It was confirmed that an interlayer compound was formed. This intercalation compound was dispersed in polyvinyl alcohol to form a cast film.

After cooling this film to liquid helium temperature,
1 laser beam with a wavelength of 678 nm and an intensity of 1 mw/cm ²
Holes were formed by irradiation for minutes.

Example 5 Saponite dispersed in distilled water [compositional formula: Na _0.49
Mg _0.14 (Al _0.83 Mg _5.97 ) i _7.20 O ₂₀ (OH) ₄ ] (manufactured by Kunimine Industries, trade name Smecton SA) 1 g contains tetra(4-N,N,N-trimethylaminophenyl)
After adding 3.8 mg of porphyne tetra(p-toluenesulfonate) (manufactured by Dojindo Laboratories), washing with distilled water, aminophenyl)
A porphyne-saponite intercalation compound was obtained. In X-ray diffraction measurements, the interlayer distance of the raw material saponite is 12.6 Å (half width of (004) 1.91°), whereas the interlayer distance of this material is 12.57 Å ((004)
It was confirmed that an intercalation compound was formed because iodine, the counteranion of the raw material porphine, was not detected in elemental analysis. This dispersion of intercalation compound was dried to form a cast film.

After cooling this film to liquid helium temperature,
1 laser beam with a wavelength of 665 nm and an intensity of 1 mw/cm ²
Holes were formed by irradiation for minutes.

Example 6 Using the same film as in Example 1, 20 to 50K
Holes were formed by irradiating laser light with a wavelength of 666 nm in the temperature range of , and the half-width of the holes is shown in Figure 2.

[Effects of the Present Invention] The optical recording material of the present invention allows for higher multiplexing and has higher hole thermal stability than conventional recording materials.

[Brief explanation of drawings]

FIG. 1 illustrates the amount of increase in the half width of the PHB hole after heating and recooling for Example 1, Example 2, and Comparative Example 1. The results of Example 1 are indicated by ▲, the results of Example 2 are indicated by ●, and the results of Comparative Example 1 are indicated by □. In Figure 2, 20 to 50K for Example 6.
This figure shows the half-width of holes formed in the temperature range of .

Claims (1)

[Scope of Claims] 1. An optical recording material characterized in that the main component is a silicate intercalation compound consisting of a porphine derivative having a cationic group and a silicate layered body. 2 A porphine derivative having a cationic group is
General formula [A] (In the formula, at least one selected from X ₁ , X ₂ , X ₃ , and X ₄ is an aryl group having a cationic group or a cationic heterocyclic group, and the others are hydrogen atoms or nonionic groups. 2. The optical recording material according to claim 1, wherein the optical recording material is a polyphine derivative represented by the following formula.