The thermal transitions of liquid crystalline polyesters have been studied by differential scanning calorimetry and thermooptical microscopy. The physical properties of these thermotropic polyesters, particularly the glass transition and the crystallization temperatures have been investigated. The influence of the spacer type on the transitions has been considered A glass transition at 64 degrees C was observed of the polyester with oxyethylenic group as flexible spacer while a glass transition could not be observed of the polyester with methylenic groups.