Nonlinear Susceptibility Experiments in a Supercooled Liquid: Evidence of Growing Spatial Correlations Close to T g

摘要: We give an overview of our recent works in which the a.c. nonlinear dielectric response archetypical glassformer (glycerol) was measured close to its glass transition temperature T g . The purpose investigate prediction that susceptibility is directly related number dynamically correlated molecules N { corr} (T). explain two susceptibilities are available, namely χ3 (3) and (1), correspond respectively cubic at third harmonics first harmonics. describe how measure these responses, even if they yield signals much smaller than linear response. show both \(\vert {\chi }_{3}^{(3)}(\omega,T)\vert\) }_{3}^{(1)}(\omega,T)\vert\) peaked as a function angular frequency ω mainly obeys critical scaling ωτα(T), where τα(T) relaxation time liquid. Both (1) decay with same power-law beyond peak. height peak increases approaches : This yields accurate determination dependence (T), once contribution saturation dipoles disentangled from dynamical glassy correlations.