AN ELECTRON-SPIN-RESONANCE STUDY OF THE EFFECT OF THERMAL HISTORY ON THE STRUCTURE OF POTASSIUM SILICATE-GLASSES

Glasses of composition 0.25K2O-0.75SiO2 have been prepared by quenching the melt with different cooling rates and their induced electron spin resonance spectra have been studied. The spectra reflect distinct structural differences in the silicate network of these glasses caused by the cooling method. Specifically slow quenching rates affect the local silicon environment in the same way as does the low temperature annealing, while faster quenching rates result in an increase in the concentration of silicon-oxygen units with two non-bridging oxygen atoms per tetrahedron.