الفهرس 
General IntroductionOnly 14 pages are availabe for public view
 |  | from | 169 |  |  |
| | | from | 169 | | |
Abstract
This work aims to the use of two and multiplebeam interferometric techniques for investigating the optothermal and optomechanical properties for both nonirradiated and irradiated monopolyester (PET) and copolyester (PETG) (polyethylene glycolmodified 4 wt. % of PET) fibres. These techniques are especially used for measuring the refractive indices, the birefringence and their profiles of fibres. These optical properties are linked with the thermal and mechanical properties of fibres via the attachment of heating and drawing devices with the interferometric techniques. Chapter (1) deals with general introduction and Review of Literature (previous work) on the fibre characterization by interferometric methods. In chapter (2) the description, basic idea and general theoretical considerations of the interferometric techniques (two and multiplebeam interference systems) are presented for the fibre investigation. Also, the basic concepts of drawing and heating setup used in optothermal and optomechanical studying of the fibre are illustrated. Chapter (3) deals with the study of the optothermal and the optomechanical properties for both nonirradiated monopolyester (PET) and copolyester (PETG) (polyethylene glycolmodified 4 wt. % of PET) fibres. The optical and structure parameters like; directional refractive index, refractive index profile, birefringence, mean molecular polarizability per unit volume, orientation function, fibre density, volume fraction of crystallinity material, weight fraction crystallinity, and volume fraction of amorphous, and the average work per chain can be calculated. The experimental work was carried out by using the optothermal and optomechanical devices combined with computerized double refracting Pluta interference microscope and multiplebeam Fizeau system in transmission.Chapter (4) studies the effect of radiation dose on the optical and structure parameter of monopolyester (PET) and copolyester (PETG) by using the computerized Pluta interference microscope. The Pluta polarizing interference microscope attached with an optothermal device is being used for determination of the refractive indices and birefringence of irradiated PET and PETG fibres using the fringe field interference method. The refractive index profiles for plan polarized light vibrating parallel (n||) and perpendicular (n<U+2534>) to the fibre axis and the structure parameters are measured at different temperatures, for the irradiated fibres. The obtained values for irradiated monopolyester (PET) are compared with those of the irradiated copolyester (PETG). Also the Pluta polarizing interference microscope attached with an optomechanical device is being used for determination of the optical and structure parameters of stretched irradiated PET and PETG at different draw ratios. Finally, the obtained results for irradiated are compared with those of the nonirradiated monopolyester (PET) and copolyester (PETG) fibres.