A systematic study of (73–x)SiO2-15Na2O-12MgO-xAl2O3 glasses, doped with 1.26mol%Eu2O3, was performed as a function of x-values of 0 to 15. The permanent change in the index of refraction was a linearly increasing function of Al2O3 concentration. The grating build-up and erasure rates also increased with Al2O3 concentrations. This was attributed to the reduced activation energy for forced diffusion of small modifiers bound to AlO4- clusters rather than to non-bridging O atoms. Ionic conductivities were also measured to confirm the reduction of the activation energies. The results supported a recently proposed model for grating kinetics in rare-earth sensitized glasses.

Effect of Al Concentration on the Holographic Grating Efficiency and Ionic Conductivity in Sodium Magnesium Aluminosilicate Glasses. A.Y.Hamad, J.P.Wicksted, M.R.Hogsed, J.J.Martin, C.A.Hunt, G.S.Dixon: Physical Review B, 2002, 65[6], 064204 (6pp)