To get an estimate of our material's overall relaxation time, we differentiate our retardance versus strain rate curves to yield a relaxation time distribution. As demonstrated by Haward et al. , the birefringence versus strain rate curves are akin to a cumulative distribution with the birefringence at a particular strain rate representing a cumulative amount of polymers being aligned at that strain rate. In these works, the relaxation time is taken to be the inverse of the strain rate and then the relaxation time is transformed to molecular weight using the power law relation , where the exponent is 1.5 for a flexible polymer. However, it has been shown that monodisperse polymers solutions do not exhibit the sharp increase in birefringence with increasing strain rate that would be expected according to this interpretation .