Carbon Crucible Technology For Optical Glass Melting

Fluoro crown and phosphate crown glasses are attractive candidates for application in the deep ultraviolet range. The calculated values for the ultraviolet resonance wavelengths are comparable with those of CaF2, BeF2 and Si02. However, the experimental ultraviolet transmission of glass is frequently limited by extrinsic absorption due to trace impurities of metal ions, mainly iron, copper and lead. The influence of different technological parameters on the ultraviolet transmission and the glass quality was investigated, especially the effect of reducing melting conditions, by using a carbon crucible in a glove box.