Relaxation Dynamics in Glass-Forming Hydrogen-Bonded Liquids

We will address the relaxation dynamics in hydrogen-bonded super-cooled liquids near (but above) the glass transition, measured via Broad-Band Dielectric Spectroscopy (BDS). We propose a theory based on decomposing the relaxation of the macroscopic dipole moment into contributions from hydrogen bonded clusters of molecules. We discuss the statistical mechanics of the super-cooled liquid and with a theoretical estimate of the relaxation time of each cluster we provide predictions for the real and imaginary part of the frequency dependent dielectric response. Using glycerol as a particular example we demonstrate quantitative correspondence between theory and experiments. The theory also demonstrates that the $\alpha$ peak and the ``excess wing'' stem from the same physics in this material.