Abstract Measurements of the charge accumulated in the active glass film up to firing as a function of the delay time in an expanded temperature range confirm our concept of charge control of the reversible switching effect in glass semiconductors. The charge required for switching is directly proportional to the film thickness. This suggests a bulk effect. Experiments with double pulses and a variable time interval between the two firing pulses lead to information on the lifetime of the accumulated charge. All experiments are in agreement with our already published model on the reversible switching effect in glass semiconductors.