الفهرس 
INTRODUCTION AND LITURATURE REVIEWOnly 14 pages are availabe for public view
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Abstract
Due to the importance of photoactive polymer films in many technological processes such as integrated optics, this thesis concerns with studying the optical properties of photoactive polymeric films especially refractive index. Also, the methods used for obtaining these properties in a simple way with high accuracy without destructing the films and the change in the refractive index due to visible light. In order to achieve this goal, samples of photoactive polymeric material were prepared by dip coating unit with different concentration of the photoactive unit. Interferometric technique was setup and tested on a glass sample with known refractive index in order to be sure from the accuracy of the setup. The samples were put in the interferometric technique to get the refractive index of the samples before and after irradiation. The absorbance spectra of the samples were measured by spectrophotometer in order to know the effect of visible light on the photoactive polymeric thin films. Also, the transmittance and reflectance spectra were measured in order to be used in the numerical method (Hadley’s method). The thesis is organized as follow: Chapter one presents an introduction to photoactive polymeric material and its important and literature review to the previous work which has been presented on the same material. Chapter two overviews the basic concepts of interference and the different ways which used for measuring the refractive index of any samples then explains how interference in thin films takes place then show the different interference pattern types. Chapter three presents the aim of the work and explains the different method for preparing thin films. It also concerns with the setup of the technique used for measuring the refractive index of the samples and the other apparatuses which used to measure the thickness of the thin films and the absorption spectra. Chapter four shows the results of the refractive indices which measured by laser interferometric technique and numerical method (Hadley’s method) and also, the absorbance, transmittance and reflectance spectra for the polymeric thin films doped with a photo active unit (DR1) and explains the reasons of the change that happened in the refractive index due to irradiation with visible light. It is observed that the absorption of the dye disperse red one (DR1) doped in polymeric material Poly (methyl methacrylate) (PMMA) increases with the increase of the concentration of the dye in the polymeric material in both cases single and double layer. It is observed also that the refractive index increases with the increase of the dye concentrations in the polymeric material without irradiation. It was founded that the value of the refractive index equal 1.5791 for the single layer sample which had concentration 7% and equal 1.5805 for the double layer one. The refractive index for the irradiated samples after one hour of visible light irradiation was measured and compared with the refractive index of the same samples without irradiation. For all the samples the refractive index increases linearly with concentrations. It was founded that the greatest change in the refractive index was at concentration 7% and equal 0.0125 for single layer sample and equal 0.0186 for the double layer sample. In general, the increase in the refractive index with dye concentrations follows the same trend for both single and double layer, and the refractive index change Δ n for double layer is higher than the single layer, because of the increasing of dye concentration in the double layer polymeric samples than the single one. In the guest-host system, azo dye guest molecules exist in their lower energy, trans form, and are randomly oriented throughout the film. Upon exposing by visible light, some of dye molecules change from trans to cis isomer and a photo stationary state is attained consisting of cis and trans isomers. The cis form has an absorption probability higher than the trans form. The reverse process, cis to trans isomer and vice versa is the reason for the increasing in the refractive index at the case of irradiation with visible light. At the end some points of future work and modifications were suggested