Patent ID: 9193622
Filing Date: 2015-11-24
Classification: C03C

Abstract:
1. An alkali-free glass having a strain point of 725° C. or higher, an average thermal expansion coefficient at from 50 to 300° C. of from 30×10 −7 to 40×10 −7 /° C., a temperature T 2 at which a glass viscosity is 10 2 dPa·s of 1,710° C. or lower, a temperature T 4 at which a glass viscosity is 10 4 dPa·s of 1,320° C. or lower, and a devitrification temperature of 1,350° C. or lower, the alkali-free glass comprising, in terms of mol % on the basis of oxides: wherein MgO+CaO+SrO+BaO is from 17 to 21, MgO/(MgO+CaO+SrO+BaO) is 0.4 or more, MgO/(MgO+CaO) is 0.4 or more, MgO/(MgO+SrO) is 0.6 or more, and the alkali-free glass does not substantially contain an alkali metal oxide.