Sodium ion migration mechanisms in silicate glasses probed by molecular dynamics simulations

Molecular dynamics simulations have been carried out on a silica glass containing 1 mol% soda. The Na distribution is not the same as that found in more highly concentrated sodium containing glasses. Long-range diffusive motion appears to be correlated with the absence of a neighboring non-bridging oxygen. Those Na ions remaining localized often show backward–forward hops that are not readily seen in glasses with larger sodium content.