Non-linear changes of performances caused by introduction of chloride ions into Er3+-doped fluorozirconate glass

The effect of chloride ions on the properties of Er3+-doped fluorozirconate glass is systematically studied. We first observed a nonlinear mutation of the glass-forming abilities and fluorescence properties of glass when 1 mol% fluoride ions were replaced by chloride ions. The results differed from previous reports. In order to explain this special phenomenon, we investigated the changes of the structure and the Judd-Ofelt theory of glass before and after halogen anion substitution. The results indicate that part of the fluorozirconium octahedral network was destroyed and transformed into a chain structure due to the bridging chlorine atoms, of which the electronegativity is lower than F-. With the increase of Cl-, the glass-forming abilities gradually recovered due to the decrease of the liquid's temperature. Therefore, a non-linear mutation of the glass-forming abilities was exhibited. Furthermore, the predictor χ, the ratio between the Judd–Ofelt parameters Ω 4 and Ω 6 , and the reduction in phonon density caused a mutation on the fluorescence properties of glass, such as the intensity and lifetime. This research could provide a new reference for the anion modification of fluoride glass.