METHOD FOR PRODUCING TIO2-SIO2 GLASS BODY,METHOD FOR HEAT-TREATING TIO2-SIO2 GLASS BODY,TIO2-SIO2 GLASS BODY,AND OPTICAL BASE FOR EUVL

摘要

The present invention relates to a process for production of a TiO 2 -SiO 2 glass body, comprising: a step of, when an annealing point of a TiO 2 -SiO 2 glass body after transparent vitrification is taken as T 1 (°C), heating the glass body after transparent vitrification at a temperature of T 1 +400°C or more for 20 hours or more; and a step of cooling the glass body after the heating step up to T 1 -400 (°C) from T 1 (°C) in an average temperature decreasing rate of 10°C/hr or less.