Patent ID: 7851394

Claim:
An alkali-free glass comprising in mole percent on an oxide basis: SiO 2 : 64.0-71.0 Al 2 O 3 : 9.0-12.0 B 2 O 3 : 7.0-12.0 MgO: 1.0-3.0 CaO: 6.0-11.5 SrO: 0-2.0 BaO: 0-0.1 wherein: (a) 1.00≦Σ[RO]/[Al 2 O 3 ]≦1.25, where [Al 2 O 3 ] is the mole percent of Al 2 O 3 and Σ[RO] equals the sum of the mole percents of MgO, CaO, SrO, and BaO; (b) the glass has the compositional characteristic that on an oxide basis, the glass comprises at least 0.01 mole percent SnO 2 ; and (c) the glass has a density that is less than or equal to 2.41 grams/cm 3 .