Patent ID: 7691763

Claim:
A float glass composition for forming a blue colored glass, comprising: a base glass portion comprising: a. SiO 2 from 66 to 75 weight percent; b. Na 2 O from 10 to 20 weight percent; c. CaO from 5 to 15 weight percent; d. MgO from 0 to 5 weight percent; e. Al 2 O 3 from 0 to 5 weight percent; f. B 2 O 3 from 0 to 5 weight percent; and g. K 2 O from 0 to 5 weight percent; and additives consisting essentially of: total iron from 0.3 to 1.2 weight percent; a first additive compound comprising Nd 2 O 3 in an amount up to 1 weight percent; CuO in an amount up to 0.3 weight percent based on the total weight of the glass composition; and optionally one or more second additive compounds selected from CoO, Cr 2 O 3 , V 2 O 5 , CeO 2 , H 2 O, SO 3 , TiO 2 , ZnO, MoO 3 , NiO, La 2 O 0.3 , WO 3 , Er 2 O 3 , SnO 2 , and MnO 2 , wherein the redox ratio of the composition ranges from 0.35 to 0.40 and the glass has a blue color characterized by a dominant wavelength in the range of 480 nm to 495 nm and an excitation purity no greater than 18 percent and an Lta of at least 70% at a thickness of 0.154 inches.