Patent ID: 7846859

Claim:
A colored glass composition having a formula of R′ 2 O—RO—SiO 2 , wherein R′ is an alkali metal element and R is an alkaline earth metal element, said colored glass composition comprising: between 0.01 and 1% by weight of molybdenum expressed as MoO 3 between 0.01 and 2.5% by weight of sulfur expressed as SO 3 , between 7.8 and 14% b weight of potassium expressed as K 2 O and between 0.68 to less than 5% b weight of sodium expressed as Na 2 O, wherein the sum of the concentrations of potassium and sodium is between 11 and 17% by weight, wherein the glass composition, expressed in percentage by weight of the oxidic forms further comprises: Component Weight % SiO 2 60-75 Al 2 O 3 0.1-7 Li 2 O 0.1-2.5 MgO 0.1-3 CaO 0.1-5 SrO 0.1-10 BaO 5-15.