Abstract
We have investigated phosphate glasses of metaphosphate composition containing three different cations Ag+, Li+ and Pr3+. Using Raman spectroscopy we study the influence of the modifier on the host structure of the glass. We observe an overall softening of the bands in the AgPO3 compared with LiPO3 and Pr(PO3)3. This effect is observed both in the high-frequency vibrational bands from the host structure and in the boson peak at low frequencies. We attribute this effect to the stronger ionic character of the Li+ and Pr3+ ions than Ag+, causing substantial ionic cross-linking of the phosphate chains in the structure.