Glassy poly(ethylene terephthalate) (PET) structures with an extraordinarily large chain orientation have been prepared from isotropic and X-ray amorphous initial film strips by applying a cold-drawing procedure with well defined parameters. Under annealing conditions, the resulting changes of the supermolecular structure and the thermomechanical behaviour are investigated. Differential scanning calorimetric studies have revealed a starting crystallization of the highly anisotropic and glassy PET structures at temperatures as low as 56 degrees C. In situ two-dimensional wide-angle X-ray scattering (WAXS) experiments have been performed to describe the formation of the crystalline order with temperature. Synchrotron WAXS investigations focusing on the (010), (<(1)over bar 10>) and (100) reflections show a fast crystallization process. The final crystal structure at each temperature above 120 degrees C is reached within less than 7.5 min. Dynamic mechanical thermal analysis, shrinkage strain and shrinkage stress measurements are discussed with respect to the relaxation of local molecular orientation as well as crystallization processes.