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Structural heterogeneity and pressure-relaxation in compressed borosilicate glasses by in situ small angle X-ray scattering

We report on Brillouin and in situ small angle X-ray scattering (SAXS) analyses of topological heterogeneity in compressed sodium borosilicate glasses. SAXS intensity extrapolated to very low angular regimes, I ( q = 0), is related to compressibility. From Brillouin scattering and analyses of the el...

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Bibliographic Details
Published in:The Journal of chemical physics 2011-05, Vol.134 (20), p.204502-204502-6
Main Authors: Reibstein, S., Wondraczek, L., de Ligny, D., Krolikowski, Sebastian, Sirotkin, S., Simon, J.-P., Martinez, V., Champagnon, B.
Format: Article
Language:English
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Summary:We report on Brillouin and in situ small angle X-ray scattering (SAXS) analyses of topological heterogeneity in compressed sodium borosilicate glasses. SAXS intensity extrapolated to very low angular regimes, I ( q = 0), is related to compressibility. From Brillouin scattering and analyses of the elastic properties of the glass, the Landau-Placzek ratio is determined and taken as a direct reflection of the amplitude of frozen-in density fluctuations. It is demonstrated that with increasing fictive pressure, topological (mid- and long-range) homogeneity of the glass increases significantly. Heating and cooling as well as isothermal scans were performed to follow the evolution of density fluctuations upon pressure recovery. For a sample with a fictive pressure p f of 470 MPa, complete recovery to p f = 0.1 MPa was observed to occur close to the glass transition temperature. The values of fictive and apparent fictive temperature, respectively, as obtained via the intersection method from plots of I ( q = 0) vs. temperature were found in good agreement with previous calorimetric analyses. Isothermal scans suggest that mid- and long-range recovery govern macroscopic density relaxation.
ISSN:0021-9606
1089-7690
DOI:10.1063/1.3593399