Platinum electrode polarization as well as its alloys with hafnium, yttrium, zirconium in the STK-12 industrial glass and also in a model melt of an equimolar mix of sodium, boron, and silicon oxides has been studied using the method of stationary voltametry. Effect of water, dissolved in a melt, on a rate of electrode processes has been estimated. The exact discharge mechanism taking into account slowed surface diffusion of absorbed univalent oxygen ions, has been proposed. Possible cathode hydrogen separation out of an oxide melt on platinum electrodes has been confirmed. Preliminary melt degasification decreases a rate of metal hydrogen absorption by an order.