Real time birefringence development of orientation in polymers during uniaxial stretching as detected by robust spectral birefringence technique

Development of Stress and Birefringence during uniaxial stretching of Polymers was studied using the newly developed stretching instrument that allows simultaneous recording of stress, spectral birefringence and strain during uniaxial deformation. In this new instrument the stretching mechanism is designed such that both upper and lower sample holding clamps move away from each other simultaneously in order to probe the birefringence at the stationary mid section of the sample. The spectral birefringence technique is robust enough to follow rapid changes in the retardation (and birefringence) as well as the reversals in the trend in birefringence that may be caused by the relaxation, crystallization and/or melting depending on the processing conditions. This deviced unique instrument will allow us to study the details of the structural ordering mechanisms real time at industrially meaningful temperatures and deformation rates