Infra-Red Spectra and the Polymorphism of Glycerides

Abstract

ALTHOUGH it is known that abrupt changes can occur in the infra-red spectra of the crystalline phase when polymorphic transitions occur¹, comparatively little use has been made of this fact to investigate polymorphic changes themselves. The purpose of this communication is to point out that the use of the infra-red technique can be extremely valuable in such cases. The speed of obtaining a spectrum can be useful in those cases where transitions are fairly rapid. Furthermore, information about the molecular structures, for example, hydrogen bonding, etc., can be obtained, and in some cases perhaps even the site symmetry of the molecules in the various polymorphic forms can be deduced.