Patent ID: 7524784

Claim:
An aluminosilicate glass comprising in mol percent on an oxide basis: 65-75 SiO 2 , 7-13 Al 2 O 3 , and 5-15 B 2 O 3 , wherein: (a) said glass has a RO/Al 2 O 3 ratio between 0.9 and 1.2, wherein R represents Mg, Ca, Sr, and Ba; (b) the glass has a CaO concentration between 5 mol percent and 15 mol percent on an oxide basis; (c) the glass has a MgO concentration between 0 mol percent and 3 mol percent on an oxide basis; and (d) the glass has a density less than about 2.45 gram/cm 3 , a liquidus viscosity greater than about 200,000 poises, and a linear coefficient of thermal expansion over the temperature range from 0° C. to 300° C. between 28×10 −7 /° C. and 35×10 −7 /° C.