Dependence of the mixed alkali effect on temperature and total alkali oxide content in y[xLi(2)O center dot (1-x)Na2O] center dot (1-y)B2O3 glasses

摘要

The complex conductivity spectra of mixed alkali borate glasses of compositions y[xLi(2)O(.)(1-x)Na2O](.)(1-y)B2O3 (with x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0; y = 0. 1, 0.2, 0.3) in a frequency range between 10(-2) Hz and 3 MHz and at temperatures ranging from 298 to 573 K have been studied. For each glass composition the conductivities show a transition from the devalues into a dispersive regime where the conductivity is found to increase continuously with frequency, tending towards a linear frequency dependence at sufficiently low temperatures. Mixed alkali effects (MAEs) in the dc conductivity and activation energy are identified and discussed. It has been for the first time found that the strength of the MAE in the logarithm of the dc conductivity linearly increases with the total alkali oxide content, y, and the reciprocal temperature, 1/T. (c) 2005 Elsevier Inc. All rights reserved.