Relaxation processes of water in the liquid to glassy states of water mixtures studied by broadband dielectric spectroscopy

The relaxation processes of water mixtures of glycerol, ethylene glycol, ethylene glycol oligomers with two to six repeat units, poly(ethylene glycol) 400 and 600, fructose, and propanol have been studied by broadband dielectric spectroscopy at different water contents in the frequency range 10 µHz–20 GHz and in the temperature range 300–80 K without water crystallization. The results show that, in the vicinity of the glass transition temperature of the mixtures, two kinds of water exist. Part of the water behaves as excess water retaining its inherent mobility and appearing as a separate relaxation process (named here the ν-process) at frequencies higher than the structural α-process at subzero temperatures. Another part of the water moves cooperatively with solute molecules and contributes to the α-process.