High refractive index silicate glass compositions with reduced devitrification kinetics

Abstract

A glass composition is provided. The glass composition includes: 25-40 wt % SiO2; 2.5-10 wt % B2O3; 0-10 wt % Al2O3; 0-15 wt % Li2O; 0-16 wt % of Li2O, Na2O, and K2O in total; 10-25 wt % CaO; 0-15 wt % BaO; 0-5 wt % MgO; 0-5 wt % SrO; 10-30 wt % CaO, BaO, MgO, and SrO in total; 0-7 wt % ZnO; 2-10 wt % ZrO; 2-15 wt % TiO2; 5-25 wt % Nb2O5; 0-5 wt % Ta2O5; 5-25 La2O3; and 0-5 wt % Y2O3. The glass composition has a refractive index from about 1.74 to about 1.80, a density from about 3.5 g/cm3 to about 4.0 g/cm3, a critical cooling rate from about 1° C./min to about 50° C./min, and a liquidus viscosity greater than 25 Poises.

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