Premium
Structure of Sodium Aluminosilicate Glasses
Author(s) -
Zirl David M.,
Garofalini Stephen H.
Publication year - 1990
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1990.tb06685.x
Subject(s) - aluminosilicate , activation energy , sodium aluminosilicate , sodium , diffusion , coordination number , aluminium , oxygen , materials science , chemistry , mineralogy , analytical chemistry (journal) , thermodynamics , metallurgy , organic chemistry , catalysis , ion , physics
A series of sodium aluminosilicate glasses composed of varying ratios ( R ) of Al 2 O 3 /Na 2 O (0.25 R 2.0) has been simulated with the molecular dynamics technique using a tetrahedral form of a three‐body interaction potential. Extrema in the activation energies for sodium diffusion and in the diffusion constants for all of the atomic species were observed for glasses with equal concentrations of Al 2 O 3 and Na 2 O ( R = 1.0). These changes corresponded to the minimum observed experimentally in the activation energy for electrical conductivity and to the maximum observed in the viscosity for glasses with compositions of R = 1.0. The coordination of aluminum remained 4 over the entire compositional range, negating the need to invoke a coordination change of aluminum to explain the changes in the physical properties. The changes to the simulated physical properties as R passed through the equivalence point were attributed to the elimination of nonbridging oxygen, to the introduction of oxygen triclusters, and to changes in the distribution of ring structures within the glass networks.