Reflectivity spectra of PbO-GeO2 glasses

Glasses of the composition of(PbO)(x)(GeO2)(1-x) with x = 0.3-0.5 were prepared by melting a mixture of starting pure oxides PbO and GeO2. The samples of the thickness of about 3 mm with perfectly polished surfaces were used for the measurement of the reflectivity spectra in the region of 2500-200 cm(-1). The observed bands in the obtained reflection spectra were compared with the published infrared absorption spectra. The observed shift of the reflection bands in the region of 750-900 cm(-1) with a change in the PbO content in the glasses correspond to those observed in the absorption spectra. This shift is ascribed to an increase in the number of non-bridging oxygen atoms per Ge tetrahedron. In the lower frequency region around 500 cm(-1) and 300 cm(-1) were observed another two reflection bands which can be probably ascribed to a O-Ge-O stretching and deformation mode, respectively.