Neutron scattering from the superionic glasses, (AgI)x(AgPO3)1−x, through the glass transition

We have performed neutron scattering measurements to study the temperature dependence of the scattering from the superionic glasses (AgI)x(AgPO3)1−x with x=0.0, 0.3, 0.5 and 0.7 between room temperature and a temperature well above the calorimetric glass transition temperature, Tg. The temperature dependence of the positions of the glass/liquid diffraction peaks is featureless except in the pure AgPO3 glass where we observe a change in the temperature derivative of the positions of the first and third peaks at Tg. We compare our results with the macroscopic thermal expansion. The peak intensities show an anomalous decrease on heating that occurs at a temperature about 5–15% higher than Tg.