The liquid crystal compound having 1, 3-dioxane unit in the mesogenic core (DIO, JNC Co.) shows anomalously high dielectric permittivity and second harmonic generation (SHG) activity in a certain temperature range. We speculate that the high dielectric permittivity results from generation of local clusters of the molecules of which dipole moment along the molecular long axis orientats unidirectionally like ferroelectrics. However, the detail of the mechanism is unclear. In this study, we investigated concentration dependence of physical characteristics of DIO. As a result, both dielectric permittivity parallel to the director and SHG intensity decreased drastically by diluting DIO with other normal nematic liquid crystals. This results clearly shows that the local ferroelectric-like orientation of DIO disappeared rapidly by dilution, suggesting that a special short-range intermolecular interaction could be responsible forthe ferroelectric-like orientation.
