Secondary dielectric relaxation in decahydroisoquinoline-cyclohexane mixture

We report dielectric relaxation measurements of the mixture 25% w/w cyclohexane in decahydroisoquinoline. Cyclohexane is a nonpolar liquid that acts as an external parameter influencing relaxation dynamics of pure decahydroisoquinoline. Two different secondary relaxation processes dominate the relaxation dynamics below the glass transition temperature, as previously observed in the pure decahydroisoquinoline. Based on the coupling model analysis we identified the fastest secondary process as the genuine secondary Johari Goldstein process, reflecting the motion of the whole molecule. On the other hand, the microscopic origin of the slowest secondary process still remains unknown. (c) 2006 Elsevier B.V. All riehts reserved.