<p>This study explores the fabrication and characterization of polyvinyl chloride (PVC)-based nanocomposite thin films functionalized with a Schiff base and embedded with zinc oxide (ZnO) and chromium oxide (Cr₂O₃) nanoparticles. The goal is to improve the optical, dielectric, and photostability properties of PVC for potential use in optoelectronic and photonic devices that operate in harsh environmental conditions. The nanocomposite films were produced using a casting method and then treated with dielectric barrier discharge (DBD) cold plasma to further enhance their surface and structural features. UV–vis spectroscopy was employed to assess optical parameters such as absorbance, reflectance, absorption coefficient, optical conductivity, and energy band gap. Fourier-transform infrared spectroscopy (FTIR) and field emission scanning electron microscopy (FESEM) were used to verify molecular interactions and nanoparticle distribution within the polymer matrix. The results showed significant improvements in optical absorption, decreased reflectance, increased dielectric constants, and a notable reduction in the optical bandgap, especially in ZnO-doped films. These increases suggest that the modified PVC films have enhanced UV resistance and are suitable for advanced applications like UV-protective coatings, light-emitting diodes (LEDs), laser sensors, and future energy conversion systems.</p>