いわゆる"グリーン・アンバー"のFTIRおよび^<13>C NMR分光分析による分子構造の研究

概要

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A peridot-like bright greenish yellow to green gem material called 'Green Amber' newly appeared in the gem market. This material is produced by treating natural resin (amber or copal) with heat and pressure in multi-stages in an autoclave. Differences in molecular structure between untreated amber and copal as compared to treated "green amber" were studied by FTIR and ^<13>C NMR spectroscopy, using powdered samples. Regardless of the starting material, the FTIR spectrum of "green amber" shows an amber pattern but with a characteristic small absorption feature at 820cm^<-1>. Solid-state ^<13>C NMR spectroscopy of the treated material indicates a significantly lower volatile component than in the untreated natural resin, evidence that the heat treatment can actually "artificially age" copal. A new absorption observed near 179ppm in the NMR spectra of all the treated samples separates them from their natural-color counterparts.
2010-03-30