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

[摘要] The Raman spectra of x%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 the Qn species 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 with x>17?mol% can be described by disproportionation reaction Q3?Q4+Q2. The enthalpy of this reaction was found to be equal to 32 ± 6, 43 ± 8, 56 ± 10, and 52 ± 9 for x=22, 27, 33, and 37?mol%, respectively. The nonideal entropy of mixing (?Smix) depends on the melt temperature and increases almost linearly with increasing temperature. The Qn, Q2–Q2, and Qn,ijkl distributions with x ranging from 0 to 55?mol% were modeled using experimental data for the concentrations of the Qn units.

[学科分类] 光谱学