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<img src='content_image/356860.jpg'>

data exhibit a clear power-law behavior with a fitted exponent − 0 . 65 ± 0 . 04, see also Fig. 2, which is close to that describing the decay of ˆ χ$_{T}$ (2 ω ). This behavior is predicted by Mode-Coupling Theory [13], and our experimental exponent is compatible with the MCT prediction − b ≃ − 0 . 6 for glycerol [23]. Note however that MCT should in fact be relevant only at temperatures much higher than the ones we focused on. Hence, the existence of a power-law regime for large ω with identical exponents for both χ$_{1}$ and χ$_{3}$ appears to be a generic property, valid outside the MCT regime. We think that this might be related to the possible incipient criticality of the system. 

We now address the question of a possible heating contribution to our results. Such ef- fects would come from the fact that applying the field E ( t ) = E cos( ωt ) across the glycerol sample leads to a dissipated power per unit volume p ( t ) ∝ ωχ ′′ $_{1}$( ω ) E $^{2}$(1 + cos(2 ωt − φ )) 

