The times to oxygen evolution at platinum electrodes in molten soda Lime silicate glass and in sodium disilicate, diborate, and diphosphate have been measured using a pulsating current technique originally introduced to study the passivity of metals in aqueous solutions. The times to oxygen evolution for the four molten electrolytes hardly varied with change in temperature, but they decreased rapidly with increased current density. As the current density and temperature were varied, the product of current density and time remained constant for a particular electrolyte, which implies that the same electrochemical reaction is occurring. The overall reaction taking place is almost certainly the discharge of nonbridging oxygen ions from the melt to evolve oxygen gas. A delay before gas evolution was caused by the formation of films on the electrode.