Dynamic scaling of QENS spectra of glassy water in aging cement paste

We propose a new method for the analysis of high-resolution incoherent quasi-elastic neutron scattering spectra of water in porous media and apply it, in particular, to a case of water in hydrated tricalcium silicate. We plot the normalized frequency-dependent susceptibility as a function of a scaling variable omega/omega(p), where omega(p) is the peak position of the alpha-relaxation. In this way, we are able to scale QENS data from a range of Q into a single master curve. We then fit this master curve with an empirical formula for the susceptibility proposed by Bergman (J. Appl. Phys. 88 (2000) 1356) to obtain three independent parameters previously introduced by us to describe the dynamic state of hydration water in a curing cement paste. Specifically, we extract q, beta, and (tau) over bar where, q is the fraction of glassy water, and beta and (tau) over bar the two parameters associated with the alpha-relaxation of the glassy water. (C) 2002 Published by Elsevier Science B.V.