| 摘要 |
It is to provide a silica glass containing TiO 2 , having a wide temperature range wherein the coefficient of thermal expansion is substantially zero. A silica glass containing TiO 2 , which has a TiO 2 concentration of from 3 to 10 mass%, a OH group concentration of at most 600 mass ppm and a Ti 3+ concentration of at most 20 mass ppm, characterized by having a fictive temperature of at most 1,200°C, a coefficient of thermal expansion from 0 to 100°C of 0±150 ppb/°C, and an internal transmittance T 400-700 per 1 mm thickness in a wavelength range of from 400 to 700 nm of at least 80%. A process for producing a silica glass containing TiO 2 , which comprises porous glass body formation step, oxygen treatment step, densification step, vitrification step and annealing step. |
