Figure 4. Aging, volume reduction and medium range ordering.

(a) Relative volume change (see text) reported as a function of t−t₀. Each temperature ramp (crosses) is followed by an isotherm. Symbols are as in Fig. 1. Inset: zoom of data at 433 K reported as a function of time from the beginning of the isotherm, together with the best fit to an exponential law. (b) Relative volume change as a function of temperature. Lines: temperature ramps; empty circles and empty squares: first and last point of an isotherm, respectively. For a better visibility, we plot only data for T≥373 K. (c) Temporal evolution of the relative change of the width of the FSDP. (d) Characteristic time for aging as obtained from the volume relaxation (τ_V, blue empty squares), the narrowing of the FSDP (τ_Γ, blue empty circles) and from XPCS data (τ*, black full dots). The average of τ_V and τ_Γ is also reported (red empty circles). Error bars correspond to the error of the fitting procedure and to error propagation for the average of τ_V and τ_Γ. Where not shown, error bars are within the symbol size.