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Title: Behavior of sodium borosilicate glasses under compression using molecular dynamics

We have performed classical molecular dynamics simulations in order to study the changes under compression in the local and medium range structural properties of three sodium borosilicate glasses with varying sodium content. These glasses have been isostatically compressed up to 20 GPa and then decompressed in order to analyze the different mechanisms that affect densification, alongside with the permanent modifications of the structure after a full compression/decompression cycle. The results show that the atomic packing is the prominent characteristic that governs the amount of densification in the glass, as well as the setup of the permanent densification. During compression, the bulk modulus increases linearly up to approximately 15 GPa and more rapidly for higher pressures, a behavior which is reflected on the rate of increase of the average coordination for B and Na. Radial distribution functions at different pressures during the cycle help to quantify the amount of distortions in the elementary structural units, with a pronounced shortening of the Na–Na and Na–O bond lengths during compression. A subsequent decomposition of the glassy matrix into elementary Voronoi volumes verifies the high compressibility of Na-rich regions.
Authors:
;  [1] ;  [2]
  1. Laboratoire Charles Coulomb (L2C), UMR 5221 CNRS-Université de Montpellier, F-34095 Montpellier (France)
  2. CEA, DEN, DTCD, SECM, F-30207 Bagnols-sur-Cèze (France)
Publication Date:
OSTI Identifier:
22493603
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 143; Journal Issue: 9; Other Information: (c) 2015 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; BOND LENGTHS; BORON; BOROSILICATE GLASS; CHEMICAL BONDS; COMPRESSIBILITY; COMPRESSION; DECOMPOSITION; MOLECULAR DYNAMICS METHOD; PRESSURE DEPENDENCE; SODIUM; SODIUM COMPOUNDS; SPATIAL DISTRIBUTION; STOWING