Patent ID: 7470642

Claim:
An aluminoborosilicate glass having a density less than 2.40 g/cm 3 and comprising the following components (in wt. %): SiO 2 58-70 Al 2 O 3 12-20 B 2 O 3 5-15 MgO 0-9 CaO 2-12 BaO 0.1-5 SnO 2 0-1 As 2 O 3 0-2, said glass, apart from random impurities, being free of SrO and free of alkali oxides; said glass further having a specific modulus of elasticity greater than 31 GPa·cm 3 ·g −1 , a modulus of elasticity greater than 71 GPa, a glass transition temperature Tg of at least 710° C., a viscosity temperature of less than 1320° C. at 10 4 dPas, and a viscosity temperature of less than 1690° C. at 10 2 dPas.