Physical properties of alkali and mixed lithium-cesium vanadate glasses prepared over an extended range of compositions

We report glass transition temperatures and density measurements of alkali and mixed alkali vanadate glasses. The glass formation of the alkali vanada te glasses (RM2O . V2O5), which required rapid cooling, occurred in the ran ge R = 0.00-1.50, where M is the alkali. We also studied the mixed alkali v anadate glasses [((RX)Li2O + R(1 - X) Cs2O) . V2O5] with R = 0.60 and X in the range 0.00-1.00, where we discovered a narrow region of bulk glass form ation centered on X = 0.60. We also compared molar volumes of the alkali va nadates to the analogous alkali phosphates [1,2]. Predicted molar volumes, determined from densities of the respective oxides, were found to closely a gree with experimental values for the glasses. Unlike the alkali borates, s ilicates, and germanates, lithium phosphates and vanadates exhibited molar volumes indicative of structural expansion. (C) 2001 Elsevier Science B.V. All rights reserved.