Isotope effect in the kinetics of crystallization of MGe32S1.35 (M = 72, 74, 76) glass

Abstract

• The especially pure M Ge 32 S 1.35 ( M = 72, 74, 76) glasses were studied by differential scanning calorimetry (DSC). • The method for processing DSC peaks for subsequent characterization of the kinetic isotope effect was developed. • The isotope effect, consisting in an increase in the crystallization temperature per unit of relative isotopic mass of Ge, was discovered. • The possibility of plotting temperature-time dependencies based on the established kinetic parameters was shown. The isotope effect of germanium ( M Ge, M = 72, 74, 76) in the crystallization kinetics of the especially pure glass-forming system M Ge 32 S 1.35 from the state of supercooled melt has been revealed and quantitatively characterized by differential scanning calorimetry (DSC) in the range 320–900 K. The data obtained in the nonisothermal regime on the increase in the crystallization temperatures of GeS (from 417.2 °C to 422.2 °C) and GeS 2 (from 489.5 °C to 491.6 °C) in the series of these compounds with 72 Ge, 74 Ge, 76 Ge isotopes were supplemented by the necessary description of the kinetic isotope effect according to the ratio of the rate constants of quasi-chemical crystallization reactions. The found parameters can be used to plot the temperature-time dependences of the crystallization degree α (t, Т ), reflecting in the form of parameters the kinetic isotope effect in the glass under study.