Spectrophotometric Studies on High Iron Content Silicate Glasses

Spectrophotometric investigations were carried out on soda-lime-silica glasses containing iron in high content, corresponding to 4.9 wt.% Fe(2)O(3), and melted under the various reducing conditions, as a part of series of studies on the redox behavior of glass. Absorption measurement was made in the range from 340 mμ to 1000 mμ. Ferric ions could not be reduced to ferrous ions completely even by the amount of carbon of four equivalents. The ratio of the strength of light absorption at 1000 mμ as a typical band of Fe(2+) ions and that at 380mμ of Fe(3+) ions was expressed as E(1000)/E(380), which was examined for glass compositions as well as various carbon amount added to glass batches. The ratio decreases as the carbon amount increases and increases with decreasing content of Na(2)O or CaO. These changes of spectrophotometric properties of glasses were discussed from the view point of state of the the iron ions. Besides, some results on oxidized glasses were also added.