Quantitative Identification of Phonon Modes Controlling the Multiphonon Relaxation in Heavy‐Metal Oxide Glasses

Abstract

The phonon mode(s) controlling the multiphonon relaxation (MPR) in PbO–Bi2O3–Ga2O3 glass was analyzed, and the effect of GeO2 addition on the MPR process was investigated. MPR rates were obtained from the lifetimes of the Tm3+:3H4 level in glasses over the temperature range 20–280 K. In PbO–Bi2O3–Ga2O3 glass, phonons from the bending vibration between GaO4 tetrahedra (∼550 cm−1) controlled the MPR process. On the addition of GeO2, the phonon mode at ∼770 cm−1 due to the stretching vibration of GeO4 tetrahedra started to affect the MPR process. Phonon modes controlling the MPR process in PbO–Bi2O3–Ga2O3–GeO2 glass were both 550 cm−1 and 770 cm−1.