Raman spectra of the SASB glasses taken at room temperature are shown in Fig. 3. Different vibrational modes existing in the glass network structures originated from the relative
arrangement of atomic or molecular units, and the amounts of bridging and non-bridging oxygen atoms, are overlapped and are appeared as broad peaks in the spectra. It is seen that the
positions, shapes and intensities of the spectra change with the amount of Al2O3. We divide the Raman spectra into three regions in wave number for convenience, 400–800, 800–1200 and 1200–1600 cm1, according to the appearance of broad peaks, and investigate the spectra in detail with deconvolution.