LAUSR

Abstract The Topological Phases (TPs) in specially homogenized equimolar GexAsxS100−2x ternary glasses are established here by performing detailed Raman scattering, together with Modulated-DSC and Volumetric measurements over a wide range of compositions, 5%  16% in the stressed-rigid phase. The novel use of ex-situ Raman profiling on the entire batch of compositions indicates very slow dynamics that is tracked with time and composition and reveals the impact of homogenization on physico-chemical properties of glasses. Stressed-Rigid glasses exceeding the chemical threshold composition are all found to be nanoscale phase separated. In the presently synthesized specially homogenized melts/glasses, we observe (i) evidence for the elusive 537 cm−1 Raman active mode of the S = As stretch in quasi-tetrahedral S = As(S1/2)3 local structure, (ii) a square-well like variation of the non-reversing enthalpy of relaxation ∆Hnr(x) at Tg displaying the Reversibility window and defining the Intermediate Phase (IP), (ii) a square-well like variation of molar volumes, Vm(x) coinciding with the IP composition range defining a Volumetric window, (iii) Melt fragility index, m(x), variation showing a global minimum in the IP compositions with m(x)  20 for non-IP compositions, defining a Fragility Anomaly, and finally a variation in the specific heat jump near Tg, ∆Cp(x), that tracks part of the observed anomalies in m(x) and ∆Hnr(x). The location of each of these anomalies/windows coinciding with those of the IP highlights the privileged nature of the window edge compositions that represent respectively rigidity- (xr = 9.0%)- and the stress- (xs = 16.0%) elastic phase transitions determined within the Topological Constraint Theory of glasses.