The high-frequency dynamics of two strong glasses, v-GeO2 and v-ZnCl2, were studied by means of inelastic neutron scattering experiments carried out with three triple-axis spectrometers in order to selectively access either a wide kinematic region or a high-energy resolution. The experimental spectra show well-defined dispersive acoustic excitations coexisting with non-dispersive waves. A thorough analysis of the inelastic line shape of longitudinal acoustic excitations provides estimates of the damping factors, which can be compared to the results of several earlier inelastic X-ray estimates for a wide class of inorganic glasses. A striking relation is observed between the microscopic damping of phonon-like modes in these glasses well below T-g and the fragility of the supercooled liquids approaching the glass transition, thus suggesting new means of investigation of the glass transition phenomenology.

Phonon-like dynamics in glasses: Coupling between damping and fragility

PETRILLO, Caterina;
2006

Abstract

The high-frequency dynamics of two strong glasses, v-GeO2 and v-ZnCl2, were studied by means of inelastic neutron scattering experiments carried out with three triple-axis spectrometers in order to selectively access either a wide kinematic region or a high-energy resolution. The experimental spectra show well-defined dispersive acoustic excitations coexisting with non-dispersive waves. A thorough analysis of the inelastic line shape of longitudinal acoustic excitations provides estimates of the damping factors, which can be compared to the results of several earlier inelastic X-ray estimates for a wide class of inorganic glasses. A striking relation is observed between the microscopic damping of phonon-like modes in these glasses well below T-g and the fragility of the supercooled liquids approaching the glass transition, thus suggesting new means of investigation of the glass transition phenomenology.
2006
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11391/921345
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