While the above two dielectric anomalies, i.e., the F-P transition of the crystalline phase and the complex βa relaxation, have been reported in many studies [25– 29], a third process, taking place at slightly higher tem-perature than the βa process, can only be observed in low-frequency dielectric spectra. Although the nature of this process (referred to as βc) is still under debate, most results support its origin in the crystallite/amorphous in-terface [33]. βc is significantly weaker than βa in the dielectric spectra, and they apparently merge into one process at frequencies above 10 kHz.