Synchrotron radiation X-ray diffraction study of polymoprhic crystalliation of SOS from liquid pahse

摘要

Kinetic properties in polymophpic crystallization of SOS (1, 3-Distearoyl-2-oleoyl-sn-glycerol) in a melt-mediated transformation have been examined in situ with a time-resolved (10 s intervals) X-ray diffraction method using synchrotron radiation (SR-XRD). It was observed hat the formation of lamellar ordering occurred more rapidly than that of the lateral subcell packing, as revealed in the seuqneial occurrence of SR-XRD long spacing and short spacing spectra. The time lag in the occurrence of the two specra increased with increasing stabiltiy of he polymorphic forms which crystallized; e.g., the formation of the sable chain packing of T in a stable β polymoprh was delayed by 500 s from the formaiton of he lamella, yet the time lage was 10-20 s in the crysallization of a metastable β' form. The behavior was singly detectable by the SR-XRD, not by a conventional XRD technique.