Natural amber, copal resin and colophony investigated by UV-VIS, infrared and Raman spectrum

Abstract

Natural amber, copal resin and colophony are have investigated by UV-VIS, infrared and Raman spectrum. In order to distinguish the natural amber, copal resin and colophony, we have successfully used the nondestructive examination (NDE) technology. The results show that UV-VIS could not distinguish these compositions. The infrared spectra can distinguish them, but the technology may destroy the specimen. The Raman spectra show three characteristic peaks of vibration near position 932 cm –1 and position 1179 cm –1 of copal resin, which confirm the existence of terpenes compounds in it. In the Raman spectra of colophony, the vibration characteristic peak at position 1589 cm –1 , caused by the conjugate double bond of internal unsaturated resin acid, is the basis of the characteristic difference between colophony and natural amber. The advantages of the distinguished technology by Raman spectroscopy are convenient and nondestructive examination for natural amber, copal resin and colophony.