Oxygen Balance In Sulfur-Containing Glass Melts

In sulfur-containing glasses the Fe2+/Fe3+ ratio at a given oxygen partial pressure shows a considerable shift compared to glasses without sulfur. This effect is caused by an electron exchange and governs the redox behaviour of industrial glass melts at fining temperature. The electron exchange is formulated by a thermodynamic approach which can quantitatively describe the redox reactions between melting temperature and room temperature in flint glasses. In amber and green glasses this dependence is superimposed by the dissolution of SO2-containing bubbles, which results in an additional shift of the oxygen partial pressure in the direction of the sulfur solubility minimum during cooling.