Effect of Thickness variation on The Optical Properties of (Poly Vinyl Alcohol : Green Methyl) Films

Abstract

Poly (vinyl alcohol) doped with different Green methyl concentration (4%) by solvent cast method for different thickness the prepare films were 5, 10, 15,and 20 µm. Transmission and absorption spectrum have been recored in order to study the effect of increasing thickness on some opttical constans such as transmittance, reflectance, absorption coefficient, refractive index and extinction coefficient. The film study reveals that all these parameters affect by increasing the thickness. The films show indirect allowed interband transitions that influenced by the thicknesses , the optical energy gap has been increased from about (3.36 eV) for the (5 µm) , (3.39 eV) for the (10 µm) , (3.41 eV) for the (15µm) and (3.45 eV) for the (20 µm).