Optical properties of polymer/chalcogenide glass composite materials

The novel composite material based on middle density polyethylene on one hand and thermoplastic chalcogenide glass on other hand has been worked out. Both materials used in the research are highly transparent in the middle and far IR but refraction indexes of components differ dramatically. The basic materials, polymer and glass, have close viscosities at the temperature of polyethylene processing. This fact allowed use of the extrusion technique for homogenization purposes. We proved, that the controlled structure of a composite could be derived through the varying of technological parameters of the mixing process. Single- and twin screw extrusion processes obtained compositions, which contain up to 50% particles of chalcogenide glass, which were dispersed in the polymer matrix. The highly homogenous compositions that contain perfect spherical glass particles of 1-2 mum in diameter dispersed into polymer matrix were obtained as well. Highly oriented structures involving chalcogenide glass fibers immersed in the polymer matrix were prepared under high stretch speeds as well. Such "fiberlike" structures exhibited pronounced polarization properties. We studied the optical properties of the composite and came to the conclusion that the controlled structure of the composite allows variation in its optical properties. It was established that it is possible to produce a composite that is opaque in the visible and near IR, and highly transparent in the 2-25-mum wave length band. Light scattering on oriented and disordered structures was studied by the IR spectro-goniometer. The novel composite which was developed by our group is intended for various IR-optics applications.