Patent ID: 6992030

Claim:
A glass material essentially free of BaO and alkali oxides and consisting essentially, by mole on an oxide basis, of the following composition: SiO 2 : 70+14 80% Al 2 O 3 : +11 3+14 9% B 2 O 3 : +11 8+14 18% CaO: +11 3+14 10% RO: +11 0+14 4% SnO: +11 0+14 0.2% XO: +11 0+14 1% where RO represents, collectively, MgO, SrO and ZnO; XO represents, collectively, TiO 2 , ZrO 2 , Y 2 O 3 and La 2 O 2 ; wherein the glass material has a strain point over 600° C., a coefficient of thermal expansion (CTE) in the range of 23×10 −7 /° C. to 35×10 −7 /° C. in the temperature range of 0–300° C., a density lower than 2.35 g/cm 3 , a liquidus temperature lower than, or equal to 1200° C. and a durability in BHF less than or equal to 0.5 mg/cm 2 weight loss.