Abstract: Banded texture was decorated on oriented films of thermotropic aromatic copolyester B─N by annealing.The fibrils of three levels,which were macrofibrils of several ten mircron in diameter,fibrils of few micron and microfibrils of about 0.3 μm,were observed by using polarized microscope.After annealing,fibrils in different levels relaxed to different morphology.Macrofibrils still oriented along shear direction,but fibrils relaxed to be helical,and microfibrils relaxed to be waveform therefore the banded texture can be seen.On the other hand,both banded texture and fibrils decorated the annealed unoriented films,that revealed the distribution of directors within and out of domains and the variation of directors on boundaries.

Key words: Copolyester, Banded texture, Annealing, Oriented film, Fibril