Effect of Structure on the Scattering Losses of Polymer Optical Fibre Materials

Abstract

Since scattering of light, together with absorption, contributes to the total loss in optical fibres, it is important to study the scattering behaviour of polymers as a function of their molecular and supramolecular structure. Light-scattering of glassy homopolymers results from anisotropy and density fluctuations. The two contributions have been studied in detail. Particular attention has been given to long-range density fluctuations which depend on the thermal history of the material. Glassy polymer mixtures and copolymers exhibit additional scattering from concentration fluctuations. This contribution has been estimated theoretically. Experiments conducted on a semicrystalline polymer indicate that transformation of a spherulitic into a fibre morphology is an interesting method to reduce the scattering loss of melt-crystallized polymers.