Modelling the OH stretch envelope shape and temperature effects in infrared spectra of hydrous silica and silicate glasses

Abstract

Simple model calculations show that the reversible temperature effects reported for broad OH-stretching bands in infrared spectra of silica, aluminosilicate, and similar glasses can be explained, in essentials, by homogeneous thermal broadening of the ν(OH) envelope constituents and a decrease in intensity with increasing temperature taking place uniformly across the band. This means that these effects are reasonably consistent with the temperature behaviour of narrow ν(OH) bands of crystalline OH-bearing minerals. These findings leave little room for the previously agreed interpretation in terms of a change in hydrogen-bonding strength, although the dependence of integrated intensity on temperature still remains to be understood.