The ionic migration in lithium borate glasses with various composition of molar ratio R (R = 0.15, 0.21, 0.33, 0.5, 0.7, 1 and 1.4) was studied by the conductivity and the nuclear magnetic resonance techniques. Four activation energies for Li ion migration characterizing these observed quantities, Eσ determined from direct-current conductivity, Ep from alternating-current conductivity, Eδω from motional narrowing phenomenon in nmr and ET1 from spin lattice relaxation rate, were obtained. The prediction of the coupling model Eσ < Eδω~ET1 does not hold. Applying a trapping model, the temperature and R dependence of ionic jump time were calculated and the results could explain successfully the experimentally determined ionic jump time τnmr for the glasses with R>0.33. The model could not be applied to the glasses (R<0.21) in which percolation transition in the hopping rate appeared.

Diffusion of Li Ion in Glassy Li2O•B2O3 System. T.Matsuo, M.Shibasaki, T.Katsumata: Solid State Ionics, 2002, 154-155, 759-66