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Title: Low-frequency inelastic light scattering in a ZBLAN (ZrF{sub 4}-BaF{sub 2}-LaF{sub 3}-AlF{sub 3}-NaF) glass

Low-frequency (down to 30 GHz) inelastic light scattering is studied in a multicomponent glass ZBLAN (ZrF{sub 4}-BaF{sub 2}-LaF{sub 3}-AlF{sub 3}-NaF) in a wide temperature range. The contributions of the THz vibrational spectrum (boson peak) and of the fast relaxation are extracted and analyzed. It is shown that the fast relaxation spectrum is described by a distribution of relaxation times leading to a power-law ν{sup α} dependence in the frequency range 30–300 GHz. Temperature dependence of α(T) is well described by the Gilroy-Phillips model, while the integrated intensity of the fast relaxation increases significantly with the temperature. This feature distinguishes the fast relaxation in ZBLAN from the case of most single-component glasses. Thermodynamic and kinetic fragility indexes are significantly different for the ZBLAN glass. The correlations between the boson peak intensity, elastic moduli, and fragility index, found earlier for single-component glasses, are fulfilled for the thermodynamic fragility index of ZBLAN. In contrast, the correlation between the fast relaxation intensity at T{sub g} and the fragility holds better for the kinetic fragility index of ZBLAN. We propose that thermodynamic and kinetic fragilities reflect different aspects of glassy dynamics in the case of glass formers with the complex chemical composition and structure topology:more » the former correlates with the elastic properties and the boson peak, the latter with the relaxation.« less
Authors:
; ;  [1] ; ;  [2]
  1. Institute of Automation and Electrometry, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090 (Russian Federation)
  2. Institute of Chemistry, Far East Branch of Russian Academy of Sciences, Vladivostok 690022 (Russian Federation)
Publication Date:
OSTI Identifier:
22252846
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 140; Journal Issue: 18; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ALUMINIUM FLUORIDES; BARIUM FLUORIDES; BOSONS; CHEMICAL COMPOSITION; ELASTICITY; GLASS; LANTHANUM FLUORIDES; LIGHT SCATTERING; RELAXATION; SODIUM FLUORIDES; SPECTRA; TEMPERATURE DEPENDENCE; TEMPERATURE RANGE; ZIRCONIUM FLUORIDES