Temperature variation of the relaxation time of alpha-dispersion for gamma-irradiated collagen.

The effect of gamma irradiation, with doses from 10(2) to 10(3) kGy, on the dielectric relaxation time of solid-state collagen was studied. Temperature measurements of the relaxation time were made over a range of frequency of the electric field from 10(1) to 10(5) Hz and at temperatures from 298 to 480 K. The samples contained 0.06 g H2O/g dry collagen. The dependencies obtained indicate that values for the relaxation time decrease with increasing temperature for all samples of collagen. In addition, an increase in the irradiation dose resulted in a decreased relaxation time for collagen at each temperature studied. These changes can be interpreted on the basis of proton conduction processes. Such effects occurring in a heterogeneous medium such as a collagen-water system are caused by the localized jumping of free protons between neighbouring sites. In the system of irradiated collagen studied, the sites are formed by structural water molecules, the products of its radiolysis and also by elements of the damaged first-order structure of the collagen macromolecule.