Form birefringence dispersion of an oriented poly(styrene-b-isoprene) triblock copolymer (SIS) with cylindrical texture

Summary We applied Wiener's theory to calculate form birefringence dispersion of an oriented block copolymer from dispersion formulas of refractive indices of bulk polymers corresponding to the blocks forming the microdomains. The nearly perfect concordance of the measured birefringence dispersion with the calculated one seems to indicate an almost complete lack of molecular orientation inside microdomains. The importance of birefringence dispersion involves modification of interference spectrum in white light. This phenomenon may induce errors when ultilizing a Berek compensator for birefringence measurements.With 16 figures