Dielectric relaxation derived from collective molecular reorientation of 9-hydroxyphenalenone in the solid state

Temperature dependence of dielectric relaxation of 9-hydroxyphenalenone (1) is measured in the frequency region of 102–107 Hz. We found a characteristic dielectric relaxation in the room temperature phase (phase II: 255–380 K), where the molecular orientation is known to be disordered. We ascribed the dielectric relaxation to the motion of boundaries between domains consisting of left- and right-directed molecules in the molecular chain.