Electrical properties of soda lime silica glass using electrolysis at 600°C between molten tin and lead electrodes

The electrolysis of a soda lime silicate glass has been studied using liquid metal electrodes of lead and tin at 600°C and voltages up to 300 V in a N₂/10% H₂ atmosphere. The behaviour observed was dependent upon the applied voltage. At less than 2.5 V, the square of the current was inversely proportional to the electrolysis time but at higher voltages, up to 100 V, the current was inversely proportional to the time for periods up to 300 ms. At voltages greater than 100 V, the behaviour could not be expressed by a simple equation, the currents passing were high and finally, electrical breakdown occurred at 300 V.It is proposed that in the range 2.5 to 100 V the glass behaves as a dielectric with charge separation in a thin surface layer. At higher voltages, near breakdown, the heat liberated at the surface is sufficient to disrupt the surface layer and then the conduction is governed by the electrical properties of the bulk glass.