Relaxations and fast dynamics of the plastic crystal cyclo-octanol investigated by broadband dielectric spectroscopy

The dielectric loss of cyclo-octanol has been investigated in a very broad frequency window of more than 17 decades. The relaxational response was traced in the plastic and the supercooled plastic phase, which are governed by the same relaxational dynamics. Experimental evidence is provided for two additional relaxational processes below the GHz region which contribute to the high-frequency wing of the alpha relaxation peaks. Near 100 GHz a loss minimum shows up which cannot be ascribed to a simple transition from the alpha relaxation to the infrared bands. As in supercooled liquids, additional fast processes seem to contribute to the dielectric response at these high frequencies.