Thermostimulated depolarization currents on a glass surface in ambient gases

Interdigital comb-shaped electrodes were used to observe thermostimulated depolarization currents flowing on a soda glass surface in ambient gases. The experimental set up, electrode shaping by photograving and measurement procedure are described. Surface thermostimulated depolarization current (STDC) spectra were recorded on glass specimens in dioxide carbon or helium. In both cases, after short gas residence times, depolarization currents were not different from those obtained in vacuum. Different STDC spectra were recorded as the residence time of a glass specimen in CO₂ was increased; these spectra also changed with polarization time and polarization temperature. In helium, STDC peaks were observed at ?110? C and ?90? C with a shoulder at ?65? C. A discussion and an attempt to interpret the results in terms of charge injection in glass involving slow adsorption or absorption of the ambient gas are given.