Abstract
A high luminosity spectrometer has been built in order to study the vibrations in oxide glasses. We compare the results obtained with this setup to those obtained with classical vibrational spectroscopies (inelastic neutron scattering, infrared absorption, Raman scattering). Selection rule analysis revealed the vibrational motions in two archetypal glasses: vitreous boron silica and vitreous boron oxide. It was necessary to base our study on xNa2O(1-x)SiO2 and xLi2O(1-x)B2O3 data and on different samples of permanent densified silica glasses. We have shown that boson peak modes in oxide glasses involve librational motions of structural rigid units composing the glass: SiO4 tetraedra in silica and boroxol ring B3O3 in v-B2O3. In both glasses we also observe that the dominant Raman and hyper-Raman lines are associated with ring vibrations.