To investigate the long-term retention characteristics of a ferroelectric-data-storage system, 80-nm-thick congruent LiTaO3 plates with inverted-domain dot arrays composed of 100-nm- Φ dots were baked at 220, 250, 280 and 300°C. After heat treatment over a range of different time intervals, the dots shrank. From the change in the dot radius data, the activation energy (Ea) and frequency factor (a), parameters of the Arrhenius equation, were determined to be = 0.76 eV, = 2.21×105. From these parameter we can predict competitive retention characteristics compared with general memory devices. The phenomenon of dot shrinking can be explained from the energy transition of the system based on wall energy.