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 vanadate glasses (RM2O·V2O5), which required rapid cooling, occurred in the range R=0.00–1.50, where M is the alkali. We also studied the mixed alkali vanadate 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 formation centered on X=0.60. We also compared molar volumes of the alkali vanadates to the analogous alkali phosphates [1,2]. Predicted molar volumes, determined from densities of the respective oxides, were found to closely agree with experimental values for the glasses. Unlike the alkali borates, silicates, and germanates, lithium phosphates and vanadates exhibited molar volumes indicative of structural expansion.