Abstract: According to the influence of OH - on the fluorescence lifetime of Er 3+ in glasses, the relations between the type/content of alkali metal ions and the content of OH - groups in erbium doped phosphate glasses were studied. The results show that, by bubbling dry O 2 and CCl 4 into the glass melt, the amount of OH - groups can be effectively reduced. At the initial stage, OH - groups were removed rather rapidly, then the process slowed down, and finally OH - groups were removed and absorbed, and reached an equilibrium. The fluorescence lifetimes of all samples with different alkali metal ions(Li +, Na + and K +) were compared, which shows the decrease of Er 3+ fluorescence lifetime with the increase of alkali metal ion diameter and O 2- volume in the glasses. It is also shown that increasing the amount of alkali metal ions would reduce the lifetime of Er 3+ , which means more OH - groups would remain in the glasses.

Key words: bium-doped, phosphate glass, alkali-metal ion, fluorescence lifetime, bubbling gas