title: Relaxation and crystallization of amorphous carbamazepine studied by terahertz pulsed spectroscopy.
abstract: At the example of carbamazepine the crystallization of a small organic molecule from its amorphous phase was studied using in situ variable temperature terahertz pulsed spectroscopy (TPS). Even though terahertz spectra of disordered materials in the glassy state exhibit no distinct spectral features we demonstrate subtle changes in the spectra with increasing temperature and discuss the findings in respect to the density of vibrational states. The crystallization leads to distinct spectral features allowing the crystallization and subsequent polymorphic phase transition at higher temperatures to be studied in detail. It is possible to study both relaxation and crystallization processes by variable temperature TPS.
authors: School of Pharmacy, University of Otago, P.O. Box 913, Dunedin, New Zealand.
authors: J Axel
authors: JA
authors: Zeitler
authors: Philip F
authors: PF
authors: Taday
authors: Michael
authors: M
authors: Pepper
authors: Thomas
authors: T
authors: Rades
mesh_terms: D000927:Anticonvulsants / Q000737:chemistry*; D002220:Carbamazepine / Q000737:chemistry*; D003460:Crystallization; D008956:Models, Chemical; D044367:Phase Transition; D017550:Spectroscopy, Fourier Transform Infrared; D013678:Technology, Pharmaceutical / Q000379:methods*; D044366:Transition Temperature; D014732:Vibration
chemical_list: D000927:Anticonvulsants; D002220:Carbamazepine