JP2000128575A - Glass composition for photobleaching, glass for photobleaching, and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a glass in which coloring and decolorization are performed to the inner part of the glass. SOLUTION: This glass has dispersed silver colloid particles and contains 30 to 69.6 mol% P2O5, 30 to 69.9 mol% MgO+CaO+SrO+BaO+ZnO and 0.1 to 25 mol% Ag calculated as Ag2O. The glass is irradiated with light of 450 to 900 nm wavelength at 1×101 to 1×105 MW/cm2 peak power density.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass which is decolorized when irradiated with light.

[0002]

2. Description of the Related Art It is already known that an irradiated portion is decolorized by irradiating a glass colored with a metal colloid with a pulse laser. For example, in J.I. A
ppl. Phys. , 83, 3795 (1998), O
pt. Lett. , 22, 967 (1997),
It has been shown that silver colloid can be introduced into glass by an ion exchange method to be colored, and that the glass can be decolorized by irradiation with laser light.

However, since the silver colloid is introduced by the ion exchange method, the coloring and decoloring are limited to the surface portion of the glass, and the coloring and decoloring cannot be performed even inside the glass.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a glass in which coloring and decoloring are performed to the inside of the glass.

[0005]

SUMMARY OF THE INVENTION The present invention substantially relates to P
₂ O ₅ and 30 to 69.9 mol%, MgO, CaO, Sr
O, from 30 to 69.9 mol% BaO and the total content of one or more of selected from the group consisting of ZnO, 0.1 to 25 mol% of Ag in the Ag ₂ O in terms, photobleach glass composition containing and, substantially, the P ₂ O ₅ 30~69.9
Mol%, MgO, CaO, SrO, BaO and ZnO
At least one selected from the group consisting of 30 to 69.
9 mol%, Ag is 0.1 to 25 mol% in terms of Ag ₂ O,
A glass for photobleaching, in which silver colloid particles are dispersed, and substantially P ₂ O ₅
From 30 to 69.9 mol%, MgO, CaO, SrO, B
0 aO-and one or more selected from the group consisting of ZnO from 30 to 69.9 mol% in total, the Ag in Ag ₂ O conversion.
A glass containing 1 to 25 mol%, which has a colored portion and a decolorized portion, and has been photobleached in which the difference between the absorption coefficient of the colored portion and the decolorized portion at each wavelength of 450 nm is 1 cm ^-1 or more. Provide glass,

In addition, P ₂ O ₅ is substantially changed from 30 to 69.9.
Mol%, MgO, CaO, SrO, BaO and ZnO
At least one selected from the group consisting of 30 to 69.
9 mol%, Ag is 0.1 to 25 mol% in terms of Ag ₂ O,
After melting the containing glass, 350-550 ° C. for 1 minute-1
A method for producing a glass for photobleaching to be held for 00 hours,
And a wavelength of 450 for the glass for photobleaching.
９００900 nm light at 1 × 10 ^{1 -1} × 10 ⁵ MW / cm ²
A method for producing photobleached glass irradiated with a peak power density of

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The term "photobleaching" as used in the present invention means decolorization by irradiating light. The photobleached glass referred to in the present invention refers to a glass having a colored portion and a portion decolorized by photobleaching (hereinafter, referred to as a decolorized portion). The glass for photobleaching as referred to in the present invention is a colored glass that is decolorized by light irradiation.

[0008] The composition of the glass composition for photobleaching of the present invention will be described by simply expressing mol% as%. P
_When the content of ₂ O ₅ is less than 30%, formation of glass becomes difficult. It is preferably at least 35%. If it exceeds 69.9%, the water resistance of the glass decreases. Preferably it is 65% or less.

[0009] MgO, CaO, SrO, BaO or Z
When nO is used in combination with P ₂ O ₅ , vitrification is facilitated, and the glass can contain Ag ₂ O at a high concentration. If the combined amount is less than 30%, the water resistance of the glass will decrease. It is preferably at least 35%. 69.
If it exceeds 9%, formation of glass becomes difficult. Preferably 65
% Or less.

Ag forms silver colloid particles in glass
It is an essential component to perform. The silver colloid particles are
It is to color the lath and make the glass a colored glass,
The light-irradiated portion of the colored glass is a decolorized portion.
Things. Below, the content of Ag is Ag_TwoConvert to O
% By mole, and simply Ag_TwoIt is called O content. Ag _Two
When the O content is less than 0.1%, coloring becomes insufficient. Like
Or more than 1%. If over 25%, glass formation is difficult
It becomes difficult. Preferably it is 20% or less.

In addition to the above, Al ₂ O ₃ , B ₂ O _{3 and the} like may be contained as components other than the above, for example, in order to suppress devitrification during glass production and facilitate glass formation.
The total amount of components other than the above is 5% or less.

The method for producing the glass composition for photobleaching of the present invention is not particularly limited. For example, mix the ingredients,
Mix, put in a platinum crucible, alumina crucible or quartz crucible, melt at 800-1300 ° C. in air, cast the obtained molten glass into a mold, and cool.

In the glass for photobleaching of the present invention, the silver colloid particles dispersed in the glass are those that make the glass a colored glass and that the light-irradiated part of the colored glass is a decolorized part. It is.

The glass for photobleaching of the present invention has light absorption by colloidal silver particles. That is, an absorption peak exists at a position where the wavelength is about 420 nm. The result is a colored glass.

The photobleach glass of the present invention is manufactured as follows. After melting glass having the same composition as the glass composition for photobleaching, heat treatment is performed at 350 to 550 ° C. for 1 minute to 100 hours to form silver colloid particles in the glass. If it is lower than 350 ° C., formation of silver colloid particles is insufficient. If it exceeds 550 ° C., the glass may be thermally deformed, or the silver colloid particles may be redissolved in the glass. When the holding time is less than 1 minute, formation of silver colloid particles is insufficient. Preferably, it is 10 minutes or more. If it exceeds 100 hours, the production efficiency of the glass decreases. Preferably it is 50 hours or less. The heat treatment includes a process of cooling the glass after melting. That is, the case where the glass satisfies the conditions of the heat treatment when the glass is cooled after melting is included.

In the photobleached glass of the present invention, the extinction coefficient α _C of the colored portion at a wavelength of 450 nm
Is larger than the extinction coefficient α _{B at} a wavelength of 450 nm of the decolorized portion, and the difference Δα = α _C −α _B is 1 cm ⁻¹ or more.
If it is less than 1 cm ^-1 , the difference in transmittance between the colored portion and the bleached portion is too small. It is preferably at least 5 cm ^-1 .

The photobleached glass of the present invention comprises:
It is manufactured as follows. By irradiating the glass for photobleaching of the present invention with light having a wavelength of 450 to 900 nm, the light passing portion in the glass can be photobleached. If the wavelength is less than 450 nm, the light is absorbed in resonance with the absorption of the colloidal silver particles having a wavelength of about 420 nm, so that photobleaching can be performed only near the glass surface. If the wavelength exceeds 900 nm, the light absorption of the silver colloid particles becomes too small and the photobleaching becomes insufficient. Preferably it is 850 nm or less.

The photobleach is silver colloidal particles in glass by light irradiation ionization ^{- and, (Ag → Ag + + e} )
This is an irreversible phenomenon that occurs when electrons generated by this ionization reaction are trapped in glass.

The ionization reaction proceeds depending on the peak power density of the irradiated light. When the peak power density is less than 1 × 10 ¹ MW / cm ² , the photobleach becomes insufficient. It is preferably at least 1 × 10 ² MW / cm ² . If it exceeds 1 × 10 ⁵ MW / cm ² , the glass surface is eroded by the laser abrasion phenomenon. Preferably 1
× 10 ⁴ MW / cm ² or less. The peak power density here is the energy of light per unit time and unit area, and the unit is MW / cm ² .

Light irradiation for photobleaching is performed using, for example, a laser having a pulse width of about 100 fs to 10 ns. Laser energy is E,
Assuming that the pulse width is T and the laser beam focused spot area is A, the peak power density is expressed by E / (T × A). When a laser beam having E = 10 μJ and T = 6 ns is focused on a portion having a diameter of 40 μm, the peak power density is about 1.3 × 10 ² MW / cm ² . In order to increase the laser power density, the laser energy may be increased, a laser having a small pulse width may be used, or the focused spot area may be reduced.

[0021]

EXAMPLES Raw materials were prepared, mixed and melted to have the composition (unit: mol%) shown in Table 1 to obtain a glass composition for photobleaching. Next, this glass composition was heat-treated at a heat treatment temperature (unit: ° C.) shown in Table 1 for 10 hours to form silver colloid particles in the glass, thereby obtaining a glass for photobleaching. Table 1 also shows the silver colloid particle diameter (unit: nm) determined using a transmission electron microscope.

This glass is optically polished to a thickness of 2.4 mm.
Was used as a plate-like sample. Next, using a laser having a pulse width of 6 ns collimated so as to have a beam diameter of 100 μm, light having a laser beam wavelength (unit: nm) shown in Table 1 was perpendicular to the sample surface at a repetition period of 10 Hz and 1000 Hz.
Photo-bleached glass was obtained by incidence of 0 shots (the number of integrated shots). Peak power density (unit: MW /
cm ² ) are shown in Table 1.

FIG. 1 shows the spectral transmittance curves of the bleached portion of the glass of Example 1 irradiated with laser light and the colored portion of the glass not irradiated with laser light. Further, a difference Δα (unit: c) between the absorption coefficient at a wavelength of 450 nm between the colored portion and the decolorized portion.
m ^-1 ) are shown in Table 1. Δα is 5 cm ⁻¹ or more in all of Examples 1 to 5.

[0024]

[Table 1]

[0025]

By irradiating a pulsed laser beam having a wavelength of 450 to 900 nm to a colored photobleaching glass in which silver colloidal particles are formed, the portion of the glass through which the pulsed laser beam has passed can be photobleached. .

The photobleached glass thus obtained has a high-contrast holographic image having a colored portion not irradiated with the pulsed laser beam and a bleached portion irradiated with the pulsed laser beam and photobleached. It can be used for gratings, holographic memories, three-dimensional memories, optical waveguide microarrays, and the like.

[Brief description of the drawings]

1 is a spectral transmittance curve of the photobleached glass of Example 1. FIG.

Continued on front page F-term (reference) 4G062 AA04 BB09 CC01 CC04 CC10 DA01 DB01 DC01 DD05 DD06 DE01 DE02 DE03 DE04 DE05 DE06 DF01 EA01 EA10 EB01 EC01 ED01 ED02 ED03 ED04 ED05 ED06 EE01 EE02 EE03 EF04 EF05 EF05 EF05 EG02 EG03 EG04 EG05 EG06 FA01 FA10 FB01 FC01 FD01 FE01 FF01 FG01 FH01 FJ01 FK01 FL01 GA01 GA10 GB01 GC01 GD01 GE01 HH01 HH03 HH04 HH05 HH07 HH09 HH11 HH13 HH15 HH17 KK01 JJ01 KK01 JJ01 KK01 JJ01 KK01 JJ01

Claims (5)

[Claims] (1) Substantially 30 to 69.9 mol% of P ₂ O ₅ and at least one selected from the group consisting of MgO, CaO, SrO, BaO and ZnO in a total amount of 30 to 69.9. mol%, 0.1 to 25 mol% of Ag in Ag ₂ O in terms, photobleach glass composition containing. 2. Substantially 30 to 69.9 mol% of P ₂ O ₅ and one or more selected from the group consisting of MgO, CaO, SrO, BaO and ZnO in a total amount of 30 to 69.9. A glass for photobleaching, wherein the glass contains 0.1% to 25% by mole of Ag and 0.1 to 25% by mole of Ag in terms of Ag ₂ O, wherein silver colloid particles are dispersed. 3. Substantially 30 to 69.9 mol% of P ₂ O ₅ and at least one selected from the group consisting of MgO, CaO, SrO, BaO and ZnO in a total amount of 30 to 69.9. A glass containing 0.1% to 25% by mole of Ag and 0.1 to 25% by mole of Ag in terms of Ag ₂ O, wherein a colored part and a decolorized part are present, and the absorption coefficient of the colored part and the decolorized part at a wavelength of 450 nm is measured. Photobleached glass with a difference of 1 cm ^-1 or more. 4. Substantially 30 to 69.9 mol% of P ₂ O ₅ and at least one selected from the group consisting of MgO, CaO, SrO, BaO and ZnO in a total amount of 30 to 69.9. Mol%, Ag is 0.1 to 25 mol% in terms of Ag ₂ O, and after melting the glass containing, 1 minute to 100 ° C. at 350 to 550 ° C.
A method for producing a glass for photobleaching to be kept for a long time. 5. The glass for photobleach according to claim 2, wherein light having a wavelength of 450 to 900 nm is applied to the glass for photobleaching in a range of 1 × 10 ¹ to 1 ×.
A method for producing photobleached glass which is irradiated at a peak power density of 10 ⁵ MW / cm ² .