The glassy state of matter, in contrast to crystalline solids, is characterized by a lack of long-range order. In the structure of glasses, the bond lengths and bond angles are not fixed. As a consequence the vibrational spectra of glassy substances exhibit various band shapes. The bands in these spectra are characterized by complex shapes and significant widths resulting in difficulties in the determination of the main spectral parameters, such as the number of bands, their positions and intensities. These difficulties limit the application of vibrational spectroscopy in the study of the structure of glasses. The main goal of the present work is to show that an appropriate procedure of decomposition of complex bands in the spectra makes it possible to obtain important information on the structure of solid glassy substances. The procedure proposed is based on (a) minimization of the number of bands, and (b) comparison with the spectra of crystalline analogues. The number of components in a complex band and its parameters are found by analysis of the second derivative of the spectrum, using Fourier self-deconvolution as proposed by Griffiths and Pariente (Trends Anal. Chem., 5 (1986) 209). According to the procedure proposed, the spectra of the crystalline and glassy analogues of the following substances were decomposed: SiO2 (silica), K[AlSi2O6] (leucite) and Li[AlSi2O6] (spodumene). This decomposition of the complex bands in the spectra of glassy substances meant that their structures could be more readily deduced. It was shown that as well as the bands corresponding to the crystalline analogues in the spectra of glasses, there are bands responsible for characteristic features of the structure of glasses.
