Some preliminary investigations are described in this paper to check whether the daily controlling of the redox state of glass can be performed directly in the glass factory using complementary techniques such as spectrophotometry and photoluminescence spectroscopy. The advantage of spectroscopic techniques with respect to the traditional wet chemical method is speed and simplicity of the measurement procedure (no specialised operators are required) once the whole procedure has been well established. However, the chamical method remains the absolute refrence one to be used in cases of difficult interpretations or when initial calibrations of the spectroscopic techniques are required. These calibrations should be performed using glasses produced by the same factory with the highest possible variations in ferrous and ferric iron concentrations.
