Anisotropy in a Simple Steady-State Shear Flow

Note that a frequency-dependent stress-optical coefficient C w) can be introduced by comparing the stress tensor and the relative permittivity tensor 

4 Anisotropy in a Simple Steady-State Shear Flow 

Let us consider the anisotropy of polymer system undergoing simple steady-state shear. This situation can be realised experimentally in a simple way (Tsvetkov et al. 1964). The quantity measured in experiment are the birefringence An and the extinction angle x which are defined by formulae (10.19) and (10.20), correspondingly, through components of the relative permittivity tensor. 

One can turn to equation (10.10) to find the components of the relative permittivity tensor. Using expressions for the moments (2.42), one determines the gradient dependence of the quantities for dilute polymer solutions to within second-order terms 

We can see from equation (10.27) that the stress-optical coefficient depends neither on the molecular weight of the polymer nor on the number of subchains 

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