Photoluminescence spectra from halogen molecular ions in borate glasses have been observed for the first time. When alkali halide is added to alkali borate glasses, X3 (X:halogen) molecular ions are formed. The molecules give rise to one or two absorption bands in the ultraviolet regions. In the case of Br3- in glasses, when the sample was selected with light, an emission band was observed at 1950nm. In the Cl-3, emission showed two bands at 800 and 1970nm. It was found that these spectra depend weakly on alkaline species. The disappearance temperatures of luminescence were 30 and 150K for Br3- and Cl3- respectively. Nevertheless, the emission of I3- could not detect even at 4K. (On the other hand, in some alkali halide crystals containing excess halogen, luminescence of V centres resembling that of X3- in glasses has also been observed.)
