High Refractive Index Glasses Of Stable Composition

Covers glasses prepared from a mixture of 95-50% of a glass (wt%) 60 La2O3, 40 B2O3, with 5-50% of a glass containing B2O3, at least one of ZnO and CdO, and at least one alkaline earth oxide and Li2O such that the molar ratio of the total other oxides to B2O3 in both component glasses exceeds 0.2 and the weight ratio of those oxides is at least 2. Specific compositions include 43.0 La2O3, 37.7 B2O3, 11.2 ZnO, 0.3 Li2O, 4.5 ZrO2, 3.3 WO3, giving a glass with RI=1.7332.