The use of windowing polarization for the study of multi-component glass

An attempt was made to investigate the possibility of applying thermally stimulated depolarization current (TSDC) techniques to the analysis of multi-component glasses with different relaxation mechanisms. Therefore, multi-component borosilicate glass containing the addition of Li2O, Na2O, MgO, BaO or in some cases Fe2O3, was investigated by integral and by partial TSDC measurements. Except for the usual partial peaks, which follow the applied poling window ΔTp, some additional peaks appeared independently of ΔTp. By the consideration of temperature of the partial peaks maxima versus temperature of poling it was possible to map and separate different and overlapping events. Generally, in the range 170–320 K several processes were observed. P0 with maximum at 198±2 K caused by the space charge, P1 at 228±3 K and P2 at 263±4 K caused by dipolar relaxations. The windowing technique shows a higher temperature process P3 at about 285–330 K attributed to the Maxwell–Wagner effect. Special attention was paid to the appearance of a number of single-relaxation time processes in the range of P2 caused by the interaction between the divalent ions and vacancies. Glass with Fe2O3 showed a decrease in the distribution width in P1 and P2 ranges, which corresponds to an increase in the homogeneity of the system. The addition of Fe2O3 also increased the magnitude of the depolarized current. An additional heat treatment of the glass increased the number of the single-relaxation time processes.