Physical properties of transparent optical polymers Dissertation

Physical properties of transparent optical polymers - Dissertation Examplesubstituted ethylenic) copolymer (Weber, 2003). Structural units of most of these polymers are given over in the figure 5.2. Fig. 5.2 Structural units of usual optical polymers (Martienssen and Warlimont, 2006). Because of the variations in structure, the properties such as refractive index, thermic stability, etc. vary among the different polymers (Losch et al., 1992). The properties of certain optical polymers (PC, PMMA, and ADC in comparison to glass are shown in figure 5.3. Fig. 5.3 Comparison of physical properties of glass and optical polymeric plastics PC, PMMA and ADC (Optical Polymers International, 2010). This chapter describes and compares the physical properties of common optical polymers. The future(a) physical properties will be discussed further 1. ... The scattering loss of these materials is low and their refractive indices are manageable (Jones, 1997). This allows their fabrication into waveguide structures. 5.2.1. Comparison of Refractive Index The refractive index of most transparent polymeric materials is around 1.5. As these are carbon based, their refractive indices and dispersion are very different from crystals and glass (Weber, 2003). Polyetherimide (PEI) has a refractive index higher than most other optical polymers. Other polymers with high refractive indices include polyarylsulfone, polyarylate, PC, and PS. PMMA has a refractive index of 1.491. The refractive indices of some common polymers are shown in card 5.1. The refractive index of ADC is 1.50, which compares well with that of glass. Polymer Refractive index PEI 1.658 Polyarylsulfone 1.651 Polyarylate 1.61 PS 1.590 PC 1.586 SAN 1.579 CR-39 1.504 PMMA 1.491 TPX 1.466 Table 5.1 Refractive indices of common polymeric materials. The refractive index of a polymer is influenced by the polarizability, free volume and the difference between the maximal absorption wavelength and optical wavelength of the material (Ma et al., 2002). The higher the density and the polarizability of the material, the higher will be its refractive index. unhomogeneous other polymeric materials have been used in optical focusing mechanisms. These include polyimides (PI), fluoropolymers (FP) such as Tedlar PVF, Tefzel ETFE, and Teflon FEP, and hydrocarbon polymers (HCP) like polyvinylbutyral (PVB). Among the fluoropolymers, the lowest index of refraction is that of Teflon FEP, which is completely fluorinated (French et al., 2011). It is observed that as the come of