Piezooptical effects in the tellurite glasses doped by europium and gold

We present the temperature dependence of piezooptical coefficients for three samples of TeO2–GeO2–PbO glasses doped with 0.5% of Eu2O3, 0.5% and 1% of Au2O3, after different thermoannealing times. We have established that there exist two temperatures singularities – minima in the range 655–695 K and maxima – at 850 K. It is crucial that for the glasses annealed during 61 h, at temperatures about 850 K, the anomaly of piezooptical coefficient disappears. Simultaneously the minima within the range 655–695 K changed depending on the duration of the thermoannealing which leads to low temperature shift of the minima. Towards lower temperature the piezooptical maxima occurs around 850 K and disappears after the increase of the annealing time. It is also crucial that the values of the piezooptical coefficients decrease with the enhancement of the thermoannealing. The observed temperature dependence with the piezooptical coefficients has a good correlation with the temperature dependences of the DSC. We have found that the pure glasses and glasses doped only by Au2O3 and Eu2O3 possess the piezooptical coefficients one order less with respect to the samples possessing simultaneously Au2O3 and Eu2O3.