The local segmental dynamics of polyisoprene and polystyrene will be investigated using three complementary and interactive techniques. Time-resolved optical spectroscopy will be used to observe directly the orientation autocorrelation function associated with a backbone bond in anthracene-labeled chains. C-13 NMR experiments at a range of temperatures and Larmor frequencies will be used to access some information about the correlation function associated with local dynamics in unlabeled polymers. Brownian dynamics computer simulations will provide quantitative predictions for both experiments, and new qualitative insights into the detailed mechanisms of local motions. Together these techniques will address the relationship between molecular structure and local dynamics, the role of the solvent environment in local motions, and the connection between local and global polymer motions.
