Crystallization Resistance of Optically Active GeSx〈Bi〉 Glasses

Abstract

The crystallization kinetics of extrapure bismuth-doped Ge–S glasses, GeSx〈nBi〉 (1.25 ≤ х ≤ 1.6, n = 1 at %), have been studied by differential scanning calorimetry (DSC) in the range 320–1000 K. A technique proposed for analysis of crystallization peaks offers the possibility of describing them with an accuracy comparable to that of the Erofeev semiempirical model and includes analytical expressions for the degree of crystallization, α(t,Т), further developing a simplified version of the Kolmogorov–Johnson–Mehl theory. The kinetic characteristics of glass crystallization in α(t,Т) found using this technique and graphical representation of the data in the form of a time–temperature–transition (TTT) diagram make it possible to optimize the optical fiber drawing temperature and time.