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 TiO2—SiO2 glass body, comprising: a step of, when an annealing point of a TiO2—SiO2 glass body after transparent vitrification is taken as T1 (° C.), heating the glass body after transparent vitrification at a temperature of T1+400° C. or more for 20 hours or more; and a step of cooling the glass body after the heating step up to T1−400 (° C.) from T1 (° C.) in an average temperature decreasing rate of 10° C./hr or less.