Thermally stimulated discharge current in lead borate glasses

Thermally stimulated discharge current (TSDC) measurement has been made on 50PbO-50B₂O₃ glass thermoelectrets the temperature range 303-623 K. The thermoelectret prepared at various polarizing fields E_p = 2.3, 3.4, 4.5, 5.6, 6.8 kV/cm and fixed polarizing temperature T_p = 303 K were heated with uniform heating rate of 0.058 K/sec. The short circuit discharge current has been measured for unpolarized sample also. The various TSDC parameters such as activation energy, characteristic relaxation time, attempt to escape frequency, capture cross section and charge released during the relaxation process have been determined by applying initial rise method. The various observed peaks in thermograms are discussed on the basis of space charge polarization and distribution of trap levels of charges inside the thermoelectret.