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Low temperature dynamics of glycolic and lactic acid studied by Raman spectroscopy

D, L-glycolic and L-(+) lactic acid are among most used precursors for biocompatible polymeric materials today. Poly(D, L-glycolic) acid and poly(L-(+)-lactic) acid are biodegradable materials which US Food and Drug Administration agency approved of for use as medical sutures, coatings on implants, surgical devices etc. Also, these polymers are used in packaging, cosmetic and food industry, to name just a few. Polycrystalline substances were studied by low temperature Raman spectroscopy in the 10 K – 300 K interval, using T64000 Horiba Jobin Yvon Raman spectrometer operating in the triple subtractive mode, with 514.5 nm argon green laser line as an excitation source. CCS 350 Janis Research cryostat was used for cooling the samples and special attention was given to low frequency spectra. Variation of phonon bands of both compounds regularly follows contraction of the lattice, and no band splittings or soft modes were observed (see Figs 1 and 2). Both compounds are very temperature stable. References [1] G. Cassanas, G. Kister, E. Fabrègue, , M. Morssli, L. Bardet, Spectrochim Acta 49A, 271, (1993).

Raman; glycolic acid; lactic acid. phonons; low temperature

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