Relaxation and crystallization of amorphous carbamazepine studied by terahertz pulsed spectroscopy.
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.
Zeitler
J Axel
JA
School of Pharmacy, University of Otago, P.O. Box 913, Dunedin, New Zealand.
Taday
Philip F
PF
Pepper
Michael
M
Rades
Thomas
T
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
D000927:Anticonvulsants; D002220:Carbamazepine