Thermally Activated Processes in Polymer Glasses
  A derivation is given for the Vogel-Fulcher-Tammann thermal activation law for the glassy state of a bulk polymer. Our microscopic considerations involve the entropy of closed polymer molecular chains (i.e. polymer closed strings). For thin film polymer glasses, one obtains open polymer strings in that the boundary surfaces serve as possible string endpoint locations. The Vogel-Fulcher-Tammann thermal activation law thereby holds true for a bulk polymer glass but is modified in the neighborhood of the boundaries of thin film polymers. 
V. Parihar, D. Drosdoff, A. Widom, Y.N. Srivastava