Material Selection Requirements
A transparent material propagates light by the resonant effect of the parts of its structure. Many plastics are transparent and most are translucent in unpigmented state. Some of the transparent materials are acrylics, polycarbonate, polystyrene, polysulphones, cellulosics, PVC etc. Amorphous nylons, oriented polypropylene and PET resins etc. can also be made transparent. "Transparency" is a subjective term. Most relate clarity of plastics to percent of light transmission. Plastics transmitting over 85% light are usually accepted as being transparent. Many plastics are not only transparent but are also colorless in that they do not selectively absorb certain wavelengths of light in the visible spectrum. Some other properties related to transparent materials are refractive index, light scattering, birefringence, dispersion and haze. |