Distinguishing two contributions to the nearly constant loss in ion-conducting glasses

In an effort to understand the origins of the nearly constant loss in disordered materials, we report dielectric studies of a series of sodium germanate glasses, (Na2O)(x)(GeO2)(1-x) for x=0, 0.003, 0.01, 0.03, and 0.1 at temperatures between 85 and 700 K. Analysis of the conductivity scaling for these glasses demonstrates the existence of two contributions in the near constant loss; one due to mobile cations that conforms to the same scaling properties found for ion hopping at high temperatures and the other due to the glass network which dominates at low temperatures and low ion densities.