Water-related bands in the IR absorption spectra of silicate glasses

The IR absorption spectra of K2O-CaO-BaO-SiO2, Na2O-SiO2, and window glass samples at wavenumbers from 1200 to 10000 cm(-1) are investigated, depending on sample composition and prehistory, with the dispersion analysis method using the convolution model for the complex dielectric constant. In the 1500-3700 cm(-1) region, the spectra are shown to contain 14-15 bands. Individual absorptivity maxima and the band frequencies and intensities are computed. The revision of common views on the total number and nature of the first order water-related bands in glass spectra started by the authors in their preceding papers is completed. Ten bands located throughout the 1500-3700 cm(-1) region are shown to be due to the components of the stretching modes of the bound hydroxyl groups in three different structural sites. Four bands located within the 2850-3400 cm(-1) region are confirmed to be due to the components of the asymmetric and symmetric stretching modes of the H2O molecule. The 1674 cm(-1) band found in the spectrum of a water-enriched sample only is assigned to the bending mode of the interstitial H2O molecule. No less than 10 multiphonon water-related bands are shown to occur in the 3700-7500 cm(-1) region. In the spectra of some samples, two other impurity bands around 1400 and 2600 cm(-1) are found, these bands being assigned to the stretching mode of the interstitial carbonate ion and first overtone of this mode, respectively. (C) 2003 Elsevier B.V. All rights reserved.