Group connectivity in binary silicate glasses

The medium range order of binary alkali-silicate glass is studied in terms of the groups Q(n,a1,...,an), where n stands for the number of bridging oxygen atoms, and a(1),...,a(n) indicate type of the connected Q(n) units. The Random Connectivity Model describing interconnections of Q(n) units in silicate glass was proposed and compared with the available experimental DQ Si-29 nuclear magnetic resonance (NMR) data and with data obtained from molecular dynamics (MD) simulations. Analysis of NMR revealed that basic connectivity conditions are not fulfilled. The connectivity distribution in glass prepared by MD was found to be random. (c) 2006 Elsevier B.V. All rights reserved.