An Apparatus for Dynamic Birefringence Measurement under Oscillatory Shear Flow Using an Oblique Laser Beam

Abstract

A new apparatus for simultaneous measurements of dynamic birefringence and dynamic viscoelasticity under oscillatory shear flow was developed with an oblique laser beam. Reliability of the apparatus was confirmed with the measurements on polystyrene solution and polystyrene melt, for which the stress-optical rule is known to hold valid. The values of the estimated stress-optical coefficient were reasonably in accord with the literature data. The measurement on a model supramolecular system having a linear thread-like shape showed that the breakdown of stress-optical rule at high frequencies, suggesting that this supramolecular system cannot be regarded as a simple ordinary polymeric system. This preliminary result indicates the promised advantage of the apparatus to discuss the molecular origin of the stress for complex systems.