SYNOPSISVarious azobenzene derivatives and polymers were attempted as materials for thin composite films containing a polymer, a liquid crystal, and lithium perchlorate which can undergo ionic-conductivity switching induced by light or heat. Poly (vinyl chloride) -based composite films containing enantiotropic azobenzene liquid crystals 1 exhibited significant ionicconductivity change based on thermo-and photoinduced phase transitions of 1, the temperature dependence on the ionic conductivity reflecting the enantiotropic phase transition behavior of the liquid crystals. Marked, reversible ionic-conductivity switching on alternating irradiation of UV and visible lights was attained with the composite films containing 1, especially 1 ( n = 12). Incorporation of monotropic liquid crystals 3 to the composite films allowed bistability in the temperature dependence on the ionic conductivity. Employment of a polycarbonate resin and poly(methy1 methacrylate) as the polymer material of the composite films gave similar ionic-conductivity changes to the poly (vinyl chloride) composite films, whereas polyethyleneoxide brought about some different results in the photoinduced ionic-conductivity change.

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We report on compression behaviors of oil-immersed insulating pressed-boards used in transformers for analyzing the axial vibration of windings. We examined the compression stressstrain curves of oil-immersed pressed-boards. We found that compression behaviors depended on strain rates and temperatures, that is, viscoelastic behaviors were observed. By applying the time-temperature superposition principle to the pressed-boards' compression behaviors, we obtained the relationship between the modulus of compressive elasticity and strain rate. As a result, we were able to estimate the pressedboards' compression behaviors at high compression forces at high strain rates.