Determination of the Temperature Dependence of Nanoheterogeneities of the Shear Modulus in Glasses and Supercooled Liquids Using Inelastic Light Scattering

Glasses, which are important materials for photonics, have inherent fluctuations of elastic constants on the nanometer scale. The heterogeneous elasticity theory connects these fluctuations with the boson peak, a characteristic feature of the vibrational spectra of glasses in THz frequency range. We use a version of this theory to find the temperature dependence of shear modulus nanometer-scale fluctuations in glycerol, a paradigmatic glass-former, in the supercooled and liquid state. The main input parameter of the theory is the frequency of the boson peak, determined from light scattering spectra. We measured the Landau–Placzek ratio in glycerol at the same temperatures and found out that its temperature dependence is in a good agreement with that of the normalized mean-square fluctuation of the shear modulus.