Optical Properties of Manganese-Activated Fluorozirconate Glasses

We have studied optical absorption and luminescence in fluorozirconate glasses activated with manganese, which was added to the glass batch in the form of compounds of manganese in different valence states (Mn2+ and Mn4+). The results demonstrate that, independent of its original valence state, the manganese is present in the glasses as Mn2+ and Mn3+ ions. The 300-K luminescence spectrum of the fluoride glass contains a broad green emission band due to the Mn2+4T1(G) → 6A1 transition. Its absorption spectrum contains weak bands due to Mn2+ and a relatively strong, broad band of Mn3+. Partial chlorine substitution for fluorine leads to a redshift of the luminescence bands and absorption band of manganese. The changes induced in the spectra by chlorine substitution for fluorine are due to changes in the local environment of the manganese ions.