Temperature dependence of 7Li NMR linewidth in glasses: relation between short-range ionic motion observed by NMR and long range ionic transport observed by electrical conductivity

The ionic conduction mechanism in glasses was studied by comparing 7Li NMR and the temperature dependence of the linewidth and electrical conductivity. A hypothetical conductivity for NMR (σNMR) was calculated, assuming that all the ions were moving at the same speed as observed by NMR and distributed homogeneously. It was then compared with the actual conductivity obtained (σcond). It was found that σcond/σNMR for most glasses exhibits similar values of the same order. However, some groups of glasses – super-ionic, poor conducting and mixed-alkali glasses – tended to deviate from this value.