We have studied the annihilation process of disclinations during in situ thin film polymerization of a series of aromatic liquid crystalline polyesters by using a polarizing light microscope (PLM). The decreases both in isotropic molten area during liquid crystal (LC) phase formation and in distance between LC disclination pairs during annihilation are found to follow a power law relation. However, abnormal annihilation phenomena, which have not been previously reported, are observed. A faster annihilation rate in the late stage of the annihilation process and an increase in the distance of a disclination pair can occur if the LC system is a reacting system or if the surroundings have other ongoing annihilations.