Thermal and some physical properties of glasses in the La2O3−CaO−B2O3 ternary system

Abstract

Glasses in the La2O3−CaO−B2O3 ternary system were studied. The glass forming range as determined by the appearance of the annealed cast was found to match previously published findings. Clear glasses were formed in the composition range of 5.7−19.1mol% La2O3 with constant B2O3 content of 71.4mol%, and in glasses of constant La2O3:CaO ratio of 1:4 with B2O3 content in the range of 71.4–55.0mol%. The non-linear optical crystalline phase La2Ca2B10O19 was crystallized from the clear glasses after heat treatments, as determined by powder XRD. Two types of the LaBO3 crystalline phases were detected in the partially and the fully crystallized glass compositions outside the glass forming range. Data are reported for the glass transition temperature (Tg), dilatometric softening point (Td), linear coefficient of expansion (α), onset crystallization temperature (Tx), exothermal peak temperature (TP), density (ρ) and index of refraction (nD) in the clear glasses.