In this study, Polyvinyl alcohol (PVA) with sodium iodide (NaI) were mixed to prepare flexible composite (PVA/NaI) films using the green solution casting synthesis method. Subsequently, these films were exposed to different times of nitrogen plasma (15, 30, 45, and 60 minutes) using cold plasma source. The XRD and SEM analysis were utilized to reveal effects of nitrogen beam on the structural and morphology of the treated samples, respectively. Further, the UV-Vis spectroscopic measurements were utilized to study the optical parameters of the pristine and exposed films. Other parameters were computed, such as refractive index, and dielectric constant. The plasma resonance frequency (WP) modified from 0.3x1013 Hz for the PVA/NaI to 0.41x1013, 0.34x 1013, 0.31x1013, and 0.23x1013 Hz after irradiation of 15, 30, 45 and 60 minutes of nitrogen plasma respectively. The most important aspect of this research is the optimization of composite characteristics and plasma conditions to create materials with novel properties for usage in different optical devices. The results show that the irradiated films PVA/NaI are appropriate for use as optical materials for flexible optoelectronic devices.