Silica glass containing TiO2 and process for its production
First Claim
Patent Images
1. A silica glass containing TiO2, which has a fictive temperature of at most 1,200°
- C., an OH group concentration of at most 600 ppm and a coefficient of thermal expansion of 0±
200 ppb/°
C. from 0 to 100°
C.
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Abstract
A silica glass containing TiO2, which has a fictive temperature of at most 1,200° C., an OH group concentration of at most 600 ppm and a coefficient of thermal expansion of 0±200 ppb/° C. from 0 to 100° C.
46 Citations
6 Claims
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1. A silica glass containing TiO2, which has a fictive temperature of at most 1,200°
- C., an OH group concentration of at most 600 ppm and a coefficient of thermal expansion of 0±
200 ppb/°
C. from 0 to 100°
C. - View Dependent Claims (4, 5)
- C., an OH group concentration of at most 600 ppm and a coefficient of thermal expansion of 0±
-
2. A silica glass containing TiO2, which has a fictive temperature of at most 1,100°
- C., an OH group concentration of at most 600 ppm and a coefficient of thermal expansion of 0±
200 ppb/°
C. from −
50 to 150°
C. - View Dependent Claims (3)
- C., an OH group concentration of at most 600 ppm and a coefficient of thermal expansion of 0±
-
6. A process for producing a silica glass containing TiO2, which comprises:
-
(a) a step of forming a porous glass body by depositing and growing on a target quartz glass particles obtained by flame hydrolysis of a Si precursor and a Ti precursor as glass-forming materials;
(b) a step of heating the porous glass body to a vitrification temperature to obtain a vitrified glass body;
(c) a step of heating the vitrified glass body to a temperature of at least the softening temperature and forming it in a desired shape to obtain a formed glass body; and
(d) a step of carrying out annealing treatment wherein the formed glass body is held at a temperature exceeding 500°
C. for a predetermined time, and then, the temperature is lowered to 500°
C. at an average cooling rate of at most 10°
C./hr.
-
Specification