JP2689582B2 - Porphyrin-based recording material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention utilizes the non-photochemical hole burning (hereinafter referred to as NPHB) phenomenon to multiplexly record light of different wavelengths on the same place of the same material. It relates to a possible optical recording material.

[Prior Art] The NPHB phenomenon is that only a guest molecule that absorbs light is selected by irradiating a material in which a dye as a guest component is dispersed with light with good monochromaticity at an extremely low temperature of about liquid helium temperature. It is optically excited to cause a photophysical change. Since a sharp hole can be formed in the absorption spectrum of the material due to this photophysical change, optical recording in the photon mode is possible depending on the presence or absence of the hole. Moreover, wavelength-multiplexed recording can be performed at the same location on the same material by changing the wavelength of the emitted light and recording sequentially. If this NPHB phenomenon is used, there is a possibility that the recording density will be improved about 1000 times as compared with the conventionally used optical digital recording media such as compact disk and laser disk.

The optical recording material using such NPHB phenomenon is composed of a guest which is a dye compound and a host for dispersing the guest. Conventionally, materials that use cresyl violet as the guest and polyvinyl alcohol as the host (Chemical Phy
sics, 99 (1985) 479-487) and the like are known. Photochemical hole burning (PHB) is known as a phenomenon similar to the NPHB phenomenon. In PHB, a photochemically reactive compound is used as a guest, but wavelength multiplexing recording is also possible. For example, a material in which the guest is 5,10,15,20-tetraphenylporphine and the host is polymethylmethacrylate (optical, 14 (4) 263-269), a material in which the guest is quinizarin and the host is silicate glass ( Journal of App
lied Physics, 58 (1985) 3559-3565) are known.

[Problems to be Solved by the Present Invention] However, the NPHB and PHB phenomena have a drawback that they become unstable when the temperature is higher than the liquid helium temperature, and the storage / readout of records becomes uncertain. This is partly because an irreversible structural change is thermally induced in the material and the microstructure around each guest molecule is different.

The present invention is intended to solve the drawbacks of the prior art, and an object thereof is to provide a thermally stable porphine-based recording material that suppresses thermal irreversible change.

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

“A porphyrin-based recording material comprising a composition containing a guest component and a host component as main components, wherein the guest component is a zinc porphyrin represented by 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 or an ionic heterocyclic group having an ionic group, and the other is a hydrogen atom or a nonionic group. (B) A porphyrin-based recording material, wherein the host component is a polymer compatible with the guest component. In comparison with conventional recording materials using the NPHB phenomenon, in the case of a material composed of zinc porphyrin having an ionic group and a polymer compatible with this ionic guest component, the electrostatic properties of the ionic zinc porphyrin and polymer It is presumed that the guest-host affinity is good due to the interaction, and therefore the irreversible structural change at the time of temperature rise is reduced. As a result, the increase in the full width at half maximum of the holes formed in the absorption spectrum of the material is suppressed, and the thermal stability of recording is improved.

In the present invention, at least one selected from X ₁ , X ₂ , X ₃ , and X ₄ is an aryl group having an ionic group or an ionic heterocyclic group, and the other is a hydrogen atom or a nonionic group. It is a sexual group. It may be an aryl group having an ionic group or an ionic heterocyclic group, or a cationic group, an anionic group, or a zwitterionic group, but from the viewpoint of compactness and low freedom of movement, Particularly preferred. As the cationic group, N, N, N-
Examples thereof include a trimethylaminophenyl group and an N-methylpyridinium group. As the anionic group, carboxyalkyl isocyanatomethyl phenyl group ^{_{(-C 6 H 4 CO 2 -}} ) or sulfonium isocyanatomethyl phenyl group ^{_{(-C 6 H 4 SO 3 -}} ) and the like. Further, as the zwitterionic group, N- carboxymethyl diisocyanate methyl pyridinium group ^{_{(-C 5 H 4 N + CH}} 2 CO 2 -) and N- sulphoxide isocyanatoethyl pyridinium group ^{_{(-C 5 H 4 N + CH}} 2 CH ₂ SO ₃ ^-) and the like. Further, among X ₁ , X ₂ , X ₃ , and X ₄ , other than an aryl group or an ionic heterocyclic group having an ionic group, hydrogen or a nonionic group, but as a nonionic group, Examples thereof include a phenyl group, a thienyl group and a pyridine group.

The ionic zinc porphyrin is present in the material with a suitable counterion. Ions should be selected from the viewpoint of compatibility with the polymer as the host component, but when X ₁ , X ₂ , X ₃ and X ₄ are anionic groups, they are alkali metal ions and alkaline earth ions. Metal ions, ammonium ions, hydrogen ions, etc., and when X ₁ , X ₂ , X ₃ , and X ₄ are cationic groups, I ⁻ , Br ⁻ , Cl ⁻ , p-toluenesulfonate ion, ClO _4- ^{and the} like are preferably used.

The ionic zinc porphyrin represented by the general formula [A] can be obtained by reacting ionic porphine with zinc halide. For example, when the ionic group is a cationic group, 5,10,15,20-tetra (4-methylpyridinium) porphine tetraiodide or 5,1
0,15,20-Tetra (4-N, N, N-trimethylaminophenyl) porphine tetra (p-toluene sulfonate)
It is obtained by reacting a cationic porphine such as with zinc iodide. When the ionic group is an anionic group, for example, tetrasodium 5,10,15,20-tetra (4-sulfonatophenyl) porphine or tetrasodium 5,10,15,20-tetra (4-carbonatophenyl). ) It is obtained by reacting an anionic porphine such as porphine with zinc iodide.

In the present invention, the polymer as the host component may be any polymer that is compatible with the ionic zinc porphyrin as the guest component, but a water-soluble polymer is preferable because the guest component is water-soluble. As the water-soluble polymer, polyethylene oxide, polyvinyl pyridine, polyvinyl pyrrolidone, polyacrylic acid, polymethacrylic acid, polymethacrylamide, polyacrylamide, cellulose acetate, polyhydroxyethyl methacrylate, polyvinylpyridium dichromate, sodium polyvinylbenzenesulfonate, Polyvinyl alcohol and the like are preferably used. Other than the water-soluble polymer, polyimide, which is a polar polymer, is preferably used.

The concentration of the guest component in the optical recording material of the present invention,
If it is too high, the hole transfer property is deteriorated due to energy transfer between guest molecules, and if it is too low, the S / N ratio at the time of recording and reading becomes small, which is a limitation. Therefore, the preferable guest concentration is 1 to 10 ^-5 M, and particularly preferably 10 ^-1 to 10 ^-4 M, based on the volume of the host polymer.

[Example] Hereinafter, the present invention will be described in more detail based on an example.
The present invention is not limited to this.

(Example 1) 5,10,15,20-tetra (4-N-methylpyridinium)
Porfin tetraiodide (manufactured by Wako Pure Chemical Industries) 700 m
g, zinc iodide 280 mg and pyridine 0.5 ml, distilled water 100 ml
After dissolving in, the mixture was reacted at 80 ° C for 30 minutes. The solid obtained by concentrating the reaction mixture was recrystallized with a mixed solvent of water and ethanol to obtain 400 mg of dark green crystals in a yield of 50%. 563 nm, 6 characteristic of metalloporphyrins in the absorption spectrum
There is an absorption band of 03 nm, and the content rate of zinc in elemental analysis is 5.3% (calculated value is 5.2%, within the error range)
Therefore, it was confirmed to be zinc 5,10,15,20-tetra (4-N-methylpyridinium) porphyrin tetraiodide.

Polyvinyl alcohol (degree of polymerization = 2000, degree of salting = 100)
%) 2.54 g was dissolved in 40 ml of distilled water, and then 26 mg of zinc 5,10,15,20-tetra (4-N-methylpyridinium) porphyrin tetraiodide synthesized in the present invention was added. Dry this in a petri dish to give a guest concentration of 10
^{A -2} M, 0.5 mm thick film was made.

After cooling this sample to liquid helium temperature, wavelength 613nm,
A PHB hole was formed by irradiating a laser beam having an intensity of 5 mW / cm ² for 1 minute. After this, the film is heated to a predetermined temperature,
The FWHM of the NPHB hole was measured again by cooling to the liquid helium temperature.

Further, for the same sample, a hole is formed by irradiating a laser beam having a wavelength of 620 nm in a temperature range of 4K to 40K,
The relationship between the full width at half maximum of the holes and the temperature is shown in FIG.

(Comparative Example 1) 10 g of isotactic polymethylmethacrylate (average molecular weight = 400000) was dissolved in 120 mg of toluene,
61 mg of tetraphenylporphine was added. By drying this solution in a petri dish, a guest concentration of 10 ^-2 M,
A film having a thickness of 0.5 mm was prepared and used as a control sample.
After forming the PHB hole at the liquid helium temperature in the same manner as above, the film was heated to a predetermined temperature and cooled to the liquid helium temperature again, and the half width of the PHB hole was measured.

Figure 2 shows NPHB and PH immediately after laser irradiation.
The difference between the half-value width (Γ ₀ ) of the B hole and the half-value width (Γ) after the temperature rise and re-cooling is plotted against the temperature rise temperature.
When the sample of Example 1 in which zinc 5,10,15,20-tetra (4-N-methiupyridinium) porphyrin tetraiodide was dispersed in polyvinyl alcohol was used,
The case where the sample of Comparative Example 1 in which tetraphenylporphine was dispersed in isotactic polymethylmethacrylate was used was shown by ◯. It can be seen that the sample of Example 1 has less increase in the full width at half maximum of the holes after temperature rise and recooling, and is superior in thermal stability.

[Advantages of the Present Invention] The porphyrin-based recording material of the present invention has higher thermal stability than conventional optical recording media and a high hole recovery rate after heating.

[Brief description of the drawings]

FIG. 1 illustrates the half width of the holes formed in the temperature range of 4K to 40K in Example 1. FIG. 2 illustrates the amount of increase in the full width at half maximum of the PHB holes after temperature rise and recooling for Example 1 (●) and Comparative Example 1 (◯).

Claims (1)

(57) [Claims] 1. A porphyrin-based recording material comprising a composition containing a guest component and a host component as main components, wherein the guest component is a zinc porphyrin represented by 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 or an ionic heterocyclic group having an ionic group, and the other is a hydrogen atom or a nonionic group. (B) A porphyrin-based recording material, wherein the host component is a polymer compatible with the guest component.