Optical properties and concentration dependence of BaO-GeO₂ in glass systems

We prepared novel barium germanium (BaO-GeO2) glass samples with varying BaO concentrations and inves-tigated their physical and optical properties. We analyzed the refractive indices, glass transition temperatures (T ??????s), molar volumes, and optical band gaps of the samples, which were measured and plotted against their BaO concentrations. The results showed that refractive indices, T ??????s, molar volumes, and coefficients of thermal expansion increased with BaO concentration. Raman spectra showed structural network modifications and typical Germanium glass bands. The band at similar to 529 cm-1 was assigned to vibration bonds of Ge(4)-O-Ge(4), and that at similar to 823 cm-1 was attributed to stretching vibration of non-bridging oxygen (NBO) atoms.