FLOW BIREFRINGENCE AND INTRAMOLECULAR ORI ENTATIONAL-ANISOTROPIC ORDER IN SOLUTIONS OF SOME AROMATIC POLYESTERS

A series of aromatic polyesters differing by the length of a flexible methylene chain fragment was studied using the flow birefringence tech nique. The optical shear coefficient of a polymer solution was found t o depend on the length of the flexible fragment. Problems pertaining t o the optical effects of the micro- and macroform are discussed. It is established that the optical anisotropy of the Kuhn segment exhibits, besides the general tendency to decrease with increasing flexible fra gment length in the macromolecule, certain oscillations when the numbe r of CH2 groups in the methylene fragments varies alternating from odd to even. These rather weak oscillations are related to changes in the degree of intramolecular orientational-anisotropic order in macromole cules of aromatic polyesters. It is shown that experimental values of the optical anisotropy of the Kuhn segment well coincide with the resu lts of theoretically calculations.