Infrared depth profiling studies of recrystallization in laser-amorphized poly(ethylene terephthalate)

Infrared depth profiling and time-resolved infrared spectroscopy have been used to study recrystallization in laser-amorphized films of poly(ethylene terephthalate) (PET). Laser amorphization of the sample film produces a situation in which both primary and secondary crystallization processes can be independently observed in the subsequent recrystallization of the film. The data are consistent with a model in which recrystallization is nucleated by the interface of laser-amorphized and untreated PET followed by an oriented primary growth process which propagates from this interface toward the surface of the film. Random secondary crystallization processes increase the degree of order in portions of the film which have undergone primary crystallization. Spectral features associated with various functional groups of PET show differing responses to primary and secondary crystallization processes and may provide insight into the nature of these processes.