VIBRATIONAL STUDY OF MIXED SIO2-GEO2 GLASSES

This paper presents the results of the Fourier transform infrared (FTIR) and Raman spectroscopic study of glasses in the system : SiO2(GeO2)-Al2O3-Fe2O3-K2O. The prominent features in the FTIR spectra are intense, broad bands in the 800-1200 cm-1 region due to antisymmetric stretching motions of SiO4 and GeO4 tetrahedra. The wavenumbers of these bands varies with composition of the glass (SiO2/GeO2 ratio) and they correspond to very weak Raman bands. Dominant Raman bands were found in the 400-600 cm-1 region and are mainly due to a stretch-bend mixed vibration. We note that intensity of these bands appear to remain constant for glasses with different SiO2/GeO2 ratio. We suggest that the changes observed in the vibrational spectra of SiO2-GeO2 glasses may reflect the effect of structural substitution of Ge4+ for Si4+ in the glass network. A more precise and detailed investigation will be needed to provide a better understanding of the spectra of the analysed glasses. © 1990.