Surface layers of a number of polymers have been studied with the help of the method of birefringence of light passing through the film with the angle of incidence other than normal. Two types of orientational order of molecular chain fragments relative to film surface have been found: predominantly parallel and predominantly normal. It appeared that surface layer width can reach considerable value (up to 0.6 mm). It has been shown that thermoprocessing plays an important role in formation of physical properties gradient in polymeric substance near the surface.