Raman Spectroscopy and Statistical Analysis of the Silicate Species and Group Connectivity in Cesium Silicate Glass Forming System

[摘要] The Raman spectra ofx%Cs2O-(100 −x)%SiO2(x=17, 22, 27, 33, and 37 mol%) glasses and melts were measured in the temperature range of 293 to 1553 K. The concentrations of theQnspecies were calculated as a function of the composition and temperature based on the deconvolution analysis of the spectra. It was found that a dynamic equilibrium among structural units in the melts withx>17 mol% can be described by disproportionation reactionQ3⇔Q4+Q2. The enthalpy of this reaction was found to be equal to 32 ± 6, 43 ± 8, 56 ± 10, and 52 ± 9 forx=22, 27, 33, and 37 mol%, respectively. The nonideal entropy of mixing (ΔSmix) depends on the melt temperature and increases almost linearly with increasing temperature. TheQn,Q2–Q2, andQn,ijkldistributions withxranging from 0 to 55 mol% were modeled using experimental data for the concentrations of theQnunits.

[学科分类] 光谱学