The rising curiosity in biodegradable polymers like PLLA is gaining consideration for his or her potential in next-generation biomedical units. One of many essential challenges in leveraging PLLA’s full potential is enhancing its crystallinity, because it tremendously influences mechanical, thermal, degradation, and piezoelectric properties, that are important for numerous purposes. Right here, we use thermal annealing and pressure engineering to rework the amorphous section right into a extra ordered crystalline construction. By means of numerous characterizations, we present that crystallinity elevated progressively from 34.8% in unprocessed movies to 57.4% at 100% pressure. Terahertz Time-Area Spectroscopy is employed to realize insights into the structural and dynamic properties the place we research low-frequency molecular vibrations and anisotropic properties, enabling simultaneous analysis of structural, resembling crystallinity, and optical traits. Rotational evaluation present direct proof of molecular orientation and birefringence induced by mechanical processing. These findings align strongly with the normal characterizations (XRD, WAXS, DSC, and FTIR). Piezoresponse Power Microscopy exhibits VPFM sign elevated from 0.65 ± 0.15 pm/V in unprocessed movies to six.5 ± 1.5 pm/V at 100% pressure. The in-depth work is a crucial step in gaining a deeper understanding of how the crystalline areas kind, evolve below totally different processing situations, and affect PLLA’s general properties.