Classifications

• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C3/00—Glass compositions
  • C03C3/04—Glass compositions containing silica
  • C03C3/06—Glass compositions containing silica with more than 90% silica by weight, e.g. quartz
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B19/00—Other methods of shaping glass
  • C03B19/14—Other methods of shaping glass by gas- or vapour- phase reaction processes
  • C03B19/1453—Thermal after-treatment of the shaped article, e.g. dehydrating, consolidating, sintering
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B32/00—Thermal after-treatment of glass products not provided for in groups C03B19/00, C03B25/00 - C03B31/00 or C03B37/00, e.g. crystallisation, eliminating gas inclusions or other impurities; Hot-pressing vitrified, non-porous, shaped glass products
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C21/00—Treatment of glass, not in the form of fibres or filaments, by diffusing ions or metals in the surface
  • C03C21/007—Treatment of glass, not in the form of fibres or filaments, by diffusing ions or metals in the surface in gaseous phase
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C4/00—Compositions for glass with special properties
  • C03C4/0071—Compositions for glass with special properties for laserable glass
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C4/00—Compositions for glass with special properties
  • C03C4/0085—Compositions for glass with special properties for UV-transmitting glass
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B2201/00—Type of glass produced
  • C03B2201/06—Doped silica-based glasses
  • C03B2201/07—Impurity concentration specified
  • C03B2201/075—Hydroxyl ion (OH)
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B2201/00—Type of glass produced
  • C03B2201/06—Doped silica-based glasses
  • C03B2201/20—Doped silica-based glasses doped with non-metals other than boron or fluorine
  • C03B2201/21—Doped silica-based glasses doped with non-metals other than boron or fluorine doped with molecular hydrogen
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B2201/00—Type of glass produced
  • C03B2201/06—Doped silica-based glasses
  • C03B2201/20—Doped silica-based glasses doped with non-metals other than boron or fluorine
  • C03B2201/22—Doped silica-based glasses doped with non-metals other than boron or fluorine doped with deuterium
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B2207/00—Glass deposition burners
  • C03B2207/30—For glass precursor of non-standard type, e.g. solid SiH3F
  • C03B2207/32—Non-halide
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C2201/00—Glass compositions
  • C03C2201/06—Doped silica-based glasses
  • C03C2201/20—Doped silica-based glasses containing non-metals other than boron or halide
  • C03C2201/21—Doped silica-based glasses containing non-metals other than boron or halide containing molecular hydrogen
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C2201/00—Glass compositions
  • C03C2201/06—Doped silica-based glasses
  • C03C2201/20—Doped silica-based glasses containing non-metals other than boron or halide
  • C03C2201/22—Doped silica-based glasses containing non-metals other than boron or halide containing deuterium
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C2203/00—Production processes
  • C03C2203/50—After-treatment
  • C03C2203/52—Heat-treatment
  • C03C2203/54—Heat-treatment in a dopant containing atmosphere

Definitions

• the invention relates to optical glass having high initial transmittance in the ultraviolet spectral region.
• This inventive glass is particularly useful as an optical material for optical applications in the deep ultraviolet region.
• fused silica is to be used as an optical material in optical applications in the deep UV
• the internal transmittance of the glass at the use wavelengths must be as high as possible.
• an increase in transmittance of 0.01 %/cm is significant. Accordingly, it is the object of the present invention to produce fused silica glass having improved initial transmittance, and to provide a method for producing such glass.
• the invention relates to a method of producing glass, particularly fused silica glass, having improved initial transmittance in the UV wavelength region.
• the inventive glass is produced by reacting such glass with hydrogen and/or deuterium.
• the inventive glass is produced by treating glass with hydrogen at such temperature and for a duration sufficient to cause the hydrogen to diffuse into the glass.
• Figure 2 is a subtraction spectrum of the reference glass sample from a deuterium-treated sample
• Figure 3 a is a graph comparing the transmittance of an untreated synthetic fused silica glass, with the transmittance of samples of the same glass, treated with deuterium at 350 °C;
• Figure 3 b is a graph comparing the absorbance spectra of the glasses of Figure la;
• Figure 4 is a graph comparing the infrared spectra of untreated glass with those of two samples treated with deuterium;
• Figure 5 is a graph of the change in absorbance versus the parts per million
• Figures 6a and 6b compare the absorbance spectra of untreated glass with those of the same glass treated after treatment with hydrogen at 600 °C.
• the transmittance is not as high as it could possibly be because of the presence of these metal ion impurities which may be present in the raw materials, or which may become entrapped in the glass from the environment during the manufacturing process
• these metal ion impurities do not enter the glass silicon-oxygen network, but their electric charge is compensated by the occurrence of non-bridging oxygen ions in the silicon-oxygen network.
• These non-bridging oxygen ions also contribute to absorption in the deep ultraviolet and vacuum ultraviolet spectral regions.
• the resulting structures give broad abso ⁇ tions in the UV spectral range, thereby decreasing the glass transmittance.
• the decrease in UV transmittance may be associated with a charge transfer-type abso ⁇ tion between the impurity metal ions and their non-bridging oxygen ligands, with their energy level difference lying within the energy band gap of the glass.
• one method of improving the transmittance of the glass is by reducing the charge transfer abso ⁇ tion between the metal ion impurities and the non-bridging oxygen in the glass.
• e is an electron and M +n is an impurity metal ion such as Fe and other transition metal ions for examples.
• the increased transmittance results because either or both (a) the lowering of the energy level of the OH species relative to the O " and (b) the raising of the energy level of the reduced species of the metal impurity ion.
• the ability to reduce will depend on the specific ion in question; for example, common multi-valent ions such as Fe 3+ will be easier to reduce than Na + .
• the amount of hydrogen and/or deuterium that can be diffused into the glass is dictated by the concentration in the ambient.
• concentration in the ambient The uniform concentration throughout the sample was assured by using the results of the diffusion equation with the diffusion coefficient of H 2 in SiO 2 given by:
• T temp, °K
• the required amount of hydrogen and/or deuterium will depend on the number of impurity ions and non-bridging oxygen ions present in the given glass. There is no requirement for excess molecular hydrogen and/or deuterium.
• T 0 initial transmittance
• suitable mixtures of hydrogen and inert gases such as argon or nitrogen, for example, 4% hydrogen and 96 % nitrogen, may also be used.
• Other gaseous reducing agents such as carbon monoxide can also be used Hydrogen and deuterium have the advantage that they can more readily be diffused into the glass to produce the desired reactions.
• Example 1 In order to verify the improvement of initial transmittance by high pressure hydrogen treatment, two pieces of 1 X 1.5 X 2 cm fused silica containing about 900 ppm of OH were deuterium treated at 90 atm, and 350 ° C, for 24 days. UV spectra, IR spectra and IR spectral subtractions were then obtained for the deuterium- treated samples (Tl and T2), and compared with those of the untreated sample (RI).
• Figure 3 a shows the UV transmittance spectra of untreated glass and for the two deuterium treated samples, Tl and T2, from 180 to 220 nm. The spectra were normalized to give 100% transmittance at 220 nm.
• each sample at 193 nm were 0.9262 for reference sample RI, 0.9363 for the first deuterium-treated sample Tl, and 0.9397 for the second deuterium-treated sample, T2. From the UV curves and from the transmittance numbers it is seen that there is a small but measurable improvement in transmittance in the UV after deuterium treatment.
• Figure 3b show the spectra for all three samples in absorbance. As shown, the initial absorbance of the reference sample RI was 0.0329, compared to 0.0284 and 0.0269 for deuterium-treated samples Tl and T2 respectively.
• Figure 4 shows the infrared spectra from 5000 to 2000 cm-1 of the two deuterated samples and a reference glass (RI).
• the band at 4520 cm-1 can also be used to calculate SiOH in thick samples or samples with high OH content.
• the subtractions of the untreated reference glass from the deuterium treated glasses from 3200 to 2500 cm-1 are shown in Figure 1.
• the subtraction spectra clearly show the presence of a peak at 2720 cm-1. This peak is attributed to SiOD which is the result from the deuterium treatment of the glasses, by the reaction described above.
• the shift, at 2720 cm-1 agrees well with what would be expected from isotopic substitution ofH for D.
• Example 2 Hydrogen/deuterium impregnation of fused silica samples was carried out, at 600° C, 1 atm, for 48 hours. This time was chosen in accordance with the diffusion equation for hydrogen in silica at 600° C for a 1 cm thick piece. Vacuum UV spectra ( Figures 6a and 6b), recorded before and after the low pressure hydrogen treatment show a significant increase in initial transmittance as a result of the treatment. As in Example 1 and Figures 1 through 5, we have again shown that initial transmittance is improved by hydrogen treatment. This result shows that high pressure hydrogen treatment is not necessary in order to improve initial UV transmittance in fused silica.
• samples of Corning glass codes 7940 and 7980 were subjected to 600° C, 48 hours, 1 atm hydrogen treatment.
• Table 1 compares the transmittance/cm of the glasses at 210 nm and 248 nm before and after this hydrogen treatment.
• Table 1. Transmittance/cm before and after hydrogen
• Example 3 silica was made by the densification of a powder precursor and subsequently treated in hydrogen at 600° C as above.
• the ultraviolet transmittance of the glass was measured before and after hydrogen treatment. Transmittance/cm and hydroxyl content, as determined by infrared, of the sample before and after hydrogen treatment are shown in Table 2 below.
• the present invention can be applied to any glass intended for use in the ultraviolet range to improve the initial transmittance.
• the method is applied to fused silica produced from silicon tetrachloride or a halide-free polymethylsiloxane.
• Preferred polymethylsiloxanes include, hexamethyldisiioxane, polymethylcyclosiloxane, and mixtures of these.
• the fused silica is made from a polymethylcyclosiloxane such as, octamethylcyclotetra- siloxane, decamethylcylcopentasiloxane, hexamethylcyclotrisiloxane, and mixtures of these.

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• General Chemical & Material Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Optics & Photonics (AREA)
• Manufacturing & Machinery (AREA)
• Glass Compositions (AREA)

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• 1997
  • 1997-02-28 EP EP97907924A patent/EP0885176A4/de not_active Ceased
  • 1997-02-28 JP JP9531834A patent/JP2000506117A/ja active Pending
  • 1997-02-28 WO PCT/US1997/003100 patent/WO1997032821A1/en not_active Ceased

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