Revealing the solid-like nature of glycerol at ambient temperature

We report on new dynamic measurements indicating a low frequency solid-like behaviour far above the glass transition and above the melting point in glycerol. Several tens micron thicknesses of pure (anhydrous) glycerol are deposited on highly wetting substrates. The response of the material to a mechanical stress is probed at room temperature as a function of the time and the frequency. The first type of experiment consists in measuring the linear dynamic response in a frequency range from 0.1 up to 10 rad/s. The second type of experiment consists in measuring the stress relaxation under a weak constant shear stress. In both cases, these independent experiments reveal that the glycerol exhibits a non-vanishing shear elasticity indicating a macroscopic solid-like character above its melting point. These results are compared with recent important observations reported, in particular, in the liquid state of glycerol by dielectric relaxation and in its supercooled states using low stress rheology.