Polarized microscopic texture of high birefringence spherulite

We found that the spherulite of poly(trimethylene terephthalate) (PTT) has high birefringence and shows vivid interference colors, such as yellow, blu e and green, under a polarized microscope without a sensitive tint plate. T he birefringence of the PIT spherulite-was evaluated to be co. 0.065 by usi ng the Michel-Levy chart. The extremely large birefringence seems to cause the unique and colorful image under the microscope without the plate. The b irefringence in the spherulite was found to increase with increasing a dist ance from the center of the spherulite, suggesting that ordering in spherul ite increases along the radius direction. As the crystallization temperatur e decreased, the ordering in spherulite increased.