The application of molecular dynamics computer simulation to the problem of elucidating alkali ion migration mechanisms in alkali silicate glasses was reviewed. Results were presented that helped to clarify the processes and their timing. In particular, it was shown that alkali ions jumped into empty sites. That is, the mechanisms owe more to their crystalline vacancy counterpart than to their interstitial cousins.

Alkali Ion Migration Mechanisms in Silicate Glasses Probed by Molecular Dynamics Simulations. Cormack, A.N., Du, J., Zeitler, T.R.: Physical Chemistry Chemical Physics, 2002, 4[14], 3193-7