CC BY 3.0 DENölle, Günther2024-01-082024-01-081998https://oa.tib.eu/renate/handle/123456789/14156https://doi.org/10.34657/13186Glass melts are mostly not in a chemical equilibrium with a coexisting gas phase, it does not adjust before maintaining the melt at a constant temperature and a constant gas phase for hours. But the one-phase equilibrium between several polyvalent Clements in a melt above the glass transition temperature always exists, it adjusts spontaneously. Below the transition temperature the redox State is invariably frozen-in. The calculation of redox states must be based on the matter and Charge balance (stoichiometric equations) and equilibrium relations (mass-action law). Such a calculation of Schreiber's experimental results was consistently possible. Accordingly cooled glasses are free from Cr⁶⁺, if the glass contains Fe²⁺. To achieve this one has to melt oxidized chromium-containing glasses with sufficient iron content.enghttps://creativecommons.org/licenses/by/3.0/de/660Article