ABSTRACT
Most glasses contain more or less high quantities of polyvalent elements. This results from the impurities, such as iron, in the raw materials, or polyvalent elements that
lent, which may occur in a glass melt in at least two different oxidation states, even if extreme oxidizing or reducing conditions are necessary. Besides the refining behavior, many other properties of glass melts and solid glasses depend on the type, concentration and redox ratio of polyvalent elements present. Among these, the color, i.e., the transmittivity of light in a certain wavelength, is the most important for both solid glass and the glass melt [1-3]. The first determines the product quality to a great extent and the latter the melting behavior, especially the temperature distribution within the glass tank.
