Thermokinetic behaviour of Ag-doped (GeS2)50(Sb2S3)50 glasses

•Relaxation and crystallization kinetics of Agy[(GeS2)50(Sb2S3)50](100 − y) glasses were studied.•Relaxation behavior was described in terms of TNM phenomenological model.•Relaxation kinetics way influenced only weakly by Ag doping.•Glass transition temperature decreased significantly with rising Ag content.•The Ag doping increased crystallization tendency.

The effect of Ag-doping on the thermokinetic behavior (cold crystallization and structural relaxation kinetics, glass-forming ability) of the Agy[(GeS2)50(Sb2S3)50](100 − y) glasses was studied by using differential scanning calorimetry, Raman spectroscopy and X-ray analysis – compositions up to y = 25 were included in the study. Structural relaxation kinetics was found to be only very weakly influenced by the Ag-doping; the following Tool-Narayanaswamy-Moynihan parameters were determined (within a 10% variation) for the majority of the glasses: activation energy 400 kJ mol− 1, non-linearity parameter 0.72, non-exponentiality parameter 0.85. On the other hand, the glass transition temperature decreased significantly with increasing Ag content – the effect can be explained by dilution of the original glassy matrix. Combination of these findings with the corresponding Raman spectra has shown that it is the Ge-S structural units that carry the main portion of the relaxation motions. Regarding the crystallization behavior, the Ag-doping led to decreased glass-forming ability and increased tendency of the glasses towards crystallization. The Ag-rich compositions exhibited during heating well-developed crystallization peaks driven by the autocatalytic Šesták-Berggren kinetics. The X-ray analysis has shown that in case of the Ag-rich compositions Sb and argyrodite crystallites tend to form during the melt-quench.