A crystallographic study of the second-order phase transition in bis(p-toluene sulphonate) diacetylene polymer crystals

Abstract

The second-order phase transition which occurs in bis(p-toluene sulphonate) diacetylene polymer crystals has been studied by X-ray diffraction. Measurements of the temperature dependence of the integrated intensity of Bragg reflections from several crystals provide evidence that the phase transition is very sensitive to the presence of defects. For one crystal several Friedel pair reflections have integrated intensities which are very asymmetric in the vicinity of the transition temperature. This suggests that the crystal was not centrosymmetric in this region and provides a possible explanation for the previous observation of pyroelectricity in pTS crystals.