Three-dimensional single molecule rotational diffusion in glassy state polymer films.

Measuring three-dimensional orientational motions of many individual molecules within glassy state poly(methyl methacrylate) has enabled nanoscopic probing of bulk-obscured polymer dynamics. Complementing bulk studies, the measured distributions of nanoscale barriers to rotational motion afforded by our single molecule orientational methods directly probe the spatial heterogeneity and nanoscopic alpha-relaxation dynamics deep within the glassy state.