Rheo-optical studies of a thermotropic liquid crystalline polyester

It is the authors' intention to use many optical techniques to characterize the textural change of a nematic melt during a shear deformation. These techniques include birefringence, small angle light scattering (SALS) and optical microscopic image analysis. The SALS technique is particularly useful in characterizing the orientational correlation distances within the texture 'domains'. The birefringence was measured by using the optical transmission technique. In a non-scattering, non-reflective birefringent sample, the transmittance for a monochromatic light between two cross circular polarizers can be directly converted to the sample retardation. The optical micrographs of the quenched samples have been converted into digital images, and then transformed into power spectrums by 2DFT. A typical power spectrum image is illustrated.