INTERPRETATION OF HYDRATED STATES OF SODIUM-SILICATE GLASSES BY INFRARED AND RAMAN ANALYSIS

Infrared spectra of thin films (a few micrometers) of hydrated sodium silicate glasses after heating at temperatures from 100-degrees to 400-degrees-C were measured in the spectral region from 400 to 4300 cm-1. Also, Raman spectra of hydrated glasses were measured in the region from 100 to 1400 cm-1. Water molecules in hydrated glasses were classified into three types by the bonding configuration: water molecules interacting with Si-OH groups, nonbridging oxygens, and bridging oxygens. On the basis of the fundamental bands observed here, we calculated the wave numbers of the combination-overtone bands of water molecules and SiOH groups in hydrated glasses. The calculated wave numbers satisfactorily agreed with observed wave numbers in the near-infrared region.