Abstract
We have investigated the SmA-SmC* phase transition of main-chain polyesters having a mesogenic p,p′-bibenzoate unit by means of the dielectric and electrooptic measurements. In the SmC* phase, a relaxation due to the Goldstone mode was observed at several 10 Hz. In addition, we recognized the other relaxation exhibiting softening behavior around the SmA-SmC* phase transition temperature.