A detailed study of some physical properties of Polyimide films after exposing them to oxygen plasma is presented. The structure of the sample has been analyzed by X-ray diffraction technique (XRD) and is found to be semi crystalline. Thermogravimetric Analysis (TGA) studies revealed that the thermal stability of polyimide films have improved after being exposed to oxygen plasma, at different time intervals, ranging from 1 to 5 min. Optical constants such as refractive index (n), extinction coefficient (K) and complex dielectric constant have been determined. A great dependence of the fundamental optical constants on the exposure time was noticed. Upon exposure to oxygen plasma, decrease in the refractive index was obtained. On the other hand the driving absorption coefficient (α) and consequently the optical band gap have been estimated. The real (`) and imaginary parts (``) of the dielectric constant have been determined. The dispersion parameters such as E0 (single-oscillator energy), Ed (dispersive energy) and M-1, M-3 (moments) were calculated and discussed.
Key words: Plasma deposition, X-ray diffraction (XRD), crystal structure, optical properties, thermogravimetric analysis (TGA).