ISSN: 0022-1198
CODEN: JFSCA
Published Online: 1 January 1998
Page Count: 8

Characterization of Fibers by Raman Microprobe Spectroscopy
White, GW
Supervisor, Forensic Chemistry, John Tonge Center for Forensic Sciences, Queensland

Keen, IP
Graduate student and associate professor, Center for Instrumental and Developmental Chemistry, Queensland University of Technology, Queensland

Fredericks, PM
Graduate student and associate professor, Center for Instrumental and Developmental Chemistry, Queensland University of Technology, Queensland

(Received 10 February 1997; accepted 11 June 1997)

Abstract

A set of fibers, mainly synthetic, has been examined by Raman microprobe spectroscopy. It was found that high quality spectra, requiring no sample preparation, are easy to obtain and that fibers with different molecular structure have very different Raman spectra. Fluorescence was occasionally a problem with excitation at 632.8 nm, but could be significantly reduced by using a semiconductor laser emitting at 780 nm. Fibers of the same polymer type from different manufacturers have Raman spectra which are only slightly different but which could be distinguished by the multivariate statistical technique of principal components analysis (PCA). Dyed fibers gave spectra with bands due to the polymer, but also with intense bands due to the dye, because of the high Raman cross-section of dye molecules. Extraction of the dye, followed by a spectral subtraction procedure allowed separate spectra of the polymer and the dye to be obtained.

Keywords:
forensic science, criminalistics, fibers, Raman spectroscopy, microprobe, dye

Paper ID: JFS16094J
DOI: 10.1520/JFS16094J
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