Temporal and Spatial Behavior of the Field-Induced Transition between Antiferroelectric and Ferroelectric Phases in Chiral Smectics

Abstract

Optical transmittance change and stroboscopic micrographs have been obtained in homogeneously aligned thin cells of S -MHPOBC, C 8 H 17 O– - -COO– COO- * CH(CH 3 )C 6 H 13 , and R -TFMNPOBC, C 8 H 17 O– - -COO– -COO- * CH(CF 3 )C 8 H 17 , by varying the initial applied DC voltage stepwise into the final one across the threshold. There exist two components, fast and slow, in the transmittance change due to the phase transition from antiferroelectric SmC A * to ferroelectric SmC * . The fast component is due to the pretransitional effect. The movement of the domain boundaries is responsible for the slow component. In the transmittance change due to the transition from SmC * to SmC A * , only the slow component is observed. The movement speed is mainly determined by the difference between the final and threshold voltages.