The dynamic structure model for ion transport in glasses

A model is developed for ion transport in glass which involves the creation of fluctuating pathways within a dynamically determined structure. Key features include a site memory effect which introduces vacancies appropriate to each kind of mobile ion, and a mismatch energy which emerges whenever an ion attempts to enter a different kind of site. The exploration of this model by numerical methods leads (i) to a power law relationship between ionic conductivity and cation content (now confirmed in the literature) and (ii) to the elucidation of many facets of the mixed alkali effect. It is suggested that this ‘dynamic structure’ model could form the basis for a comprehensive theory of vitreous electrolytes.