Elastic properties of diopside, anorthite, and grossular glasses and liquids: A Brillouin Scattering study up to 1400 K

Abstract

The compressional V p and shear V s wave velocities of diopside (CaMgSi 2 O 6 ), anorthite (CaAl 2 Si 2 O 8 ), and grossular (Ca 3 Al 2 Si 3 O 12 ) glasses and liquids have been measured by high‐resolution Brillouin spectroscopy up to 1200 or 1400 K. For all three materials, marked breaks in the wave velocity‐temperature relationships are observed at temperatures consistent with the glass transition temperatures observed in viscosity and calorimetry experiments. From comparisons between high‐temperature ultrasonic (relaxed V p ) data and extrapolated Brillouin (unrelaxed V p and V s ) values, the configurational compressibility of diopside and anorthite liquids has been determined. The relative importance of vibrational and configurational contributions can be markedly different for the compressibility and heat capacity of silicate melts.