ABSTRACT
Owing to the difference in their chemical structure, every polymer displays a different refractive index. The organization of the polymer chains in the solid also has a high impact on the refractive index. For example, the refractive index of the crystalline region is different from that of the amorphous region in most of the polymers. If the crystallites are larger than the wavelength of light, the difference in refractive index leads to scattering of light, consequently rendering the polymer either opaque or translucent. The utilization of change of refractive index has been adopted in a variety of applications. Multilayer polymer lms, due to the distinct refractive indices of the polymers used in individual layers, display controlled refraction or reection of the incident light. Chapter 2 discusses in detail the novel application of such gradient refractive index assemblies. The refractive index of the material can also temporarily be altered on application of an external stimulus, such as an intense light beam from a laser source. Such materials have been utilized for applications in holographic displays, which will be discussed in Chapter 3. The use of polymer-dispersed liquid crystals for fabrication of holographic displays is also discussed in Chapter 7.
