Effect of Eu3+ concentration on the grating efficiency and ionic conductivity in sodium–magnesium–aluminosilicate glasses

We report a systematic study of a grating formation in which the [Eu2O3] in sodium–magnesium–aluminosilicate glasses is varied from 0.76 to 8.11 mol %. The growth, decay, and erasure of the grating are reported as functions of the [Eu2O3]. The maximum persistent change in the index of refraction was 3×10−5. The persistent change in the index of refraction was initially a quadratic function of the [Eu2O3] and showed a limiting behavior at the highest [Eu2O3]. The transient change in the index of refraction Δntran was a quadratic function of [Eu2O3] throughout the range of concentrations studied here. The grating buildup rate increased linearly with Δntran. The results of this study are consistent with the model published recently by Dixon et al. Ionic conductivities were also measured to help separate the effect of the Eu3+ on the glass network from its active role in transferring the optical energy into ionic motion.