Identification of charge carriers and quantification of diffusion coefficients in the energy landscape of S53P4 bioglass

The ionic conduction of S53P4 glass has been investigated by a combination of electric field‐assisted ion exchange and thermal electro‐poling experiments. The dominant charge carrier being mobile in native S53P4 is identified to be the Na + ion. By means of alkali proton substitution and alkali deuteron substitution, the diffusion coefficient, D(Na + ), has been determined as a function of the local Na + concentration. It is found to vary over 2 orders of magnitude due to the distribution of site energies in the potential energy landscape of the glass. The Ca ++ ions appear immobile under the conditions of the alkali‐proton substitution technique and alkali‐deuteron substitution experiments. However, Ca ++ ions become mobile under the conditions of thermal electro‐poling. The diffusion coefficient for Ca ++ ions, D(Ca ++ ), turns out to be five orders of magnitude smaller than D(Na + ) in the bulk.