Fragility and Cooperative dynamics correlations in GexSe1-x chalcogenide glasses

Abstract In our thermal studies correlation between Cooperativity and Angell's fragility index neatly delineates homogeneous floppy, heterogeneous isostatic, and semi-homogeneous stressed rigidity-phases of the GexSe1-x system. These phases are manifestation of network evolutions due to doping of Ge into selenium polymer chains. In present experiments/data analysis distinct power law exponents (positive and negative) in fragility and cooperative dynamics correlation are observed. Their explanations are provided for three phases across GexSe1-x glass series. Temperature scanning study by ramp method was performed and data was analyzed with Vogel-Fulcher type. Isothermal measurements were performed and data was analyzed with Kohlarausch stretched exponential type. However, the Kohlrausch-Williams-Watts (KWW) nonlinearity exponent β parametrizing stretched-exponential relaxations [~ exp.{−(t/τ)β}] does not discern between the three phases, in its covariance with mAngell. In present study theoretical models for confirmation the result for correlations among properties of glasses are being suggested.