Composition dependence of crystallization behavior in binary germanium-phosphate glasses
Résumé
GeO2-P2O5 glass systems are crucial for the fabrication of fibers used in the various applications including midinfrared lasers and amplifiers. In addition to purification challenges, localized crystallization and domain structural ordering are primary obstacles in reducing loss in GeO2-P2O5 glass system. In this work, the crystallization behavior of the binary GeO2-P2O5 glasses were investigated by using calorimetric method, and subsequently, the non-isothermal crystallization kinetics parameters were derived by using an Avrami-based equation modified by KAZUMASA MATUSITA. It was found that increasing the P2O5 content leads to a transition from surface crystallization to bulk crystallization. Structural characterization revealed that the evolution of phosphate-oxide units could be highly relevant to the resistance to crystallization of the glasses, whereas changes in the degree of polymerization could affect the crystallization mode. This work has significant implications for developing low-loss fibers and enhancing their optical properties.