Spectroscopic investigations on the depth-dependent degradation gradients of aged triterpenoid varnishes

Charis Theodorakopoulos, Vassilis Zafiropulos, Jaap Boon, Stamatis Boyatzis

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)


The depth-profiles of accelerated aged triterpenoid dammar and mastic varnishes, which had been uncovered by optimized KrF excimer laser ablation (248 nm, 25 ns), were examined by ultraviolet-visible (UV/VIS) spectrophotometry and attenuated total reflection (ATR) Fourier transform infrared (FT-IR) spectroscopy. The results reflect both the optical properties at the bulk (UV/VIS) and the surface (ATR/FT-IR) and establish the presence of degradation gradients across the depth of the degraded natural resin films. It is demonstrated that the UV part of the ambient radiation is absorbed by the deteriorated surface and that the optical densities of the aged varnish decrease as a function of depth. The absorbed UV wavelengths at the surface and the depth-wise reduction of light intensity result in a depth-dependent decrease in carbonyl absorbance and an increase in C-H bending vibration modes of methylene species pointing to structural modification in the triterpenoid mixture across depth.
Original languageEnglish
Pages (from-to)1045-1051
JournalApplied Spectroscopy
Issue number10
Publication statusPublished - Oct 2007
EventSociety for Applied Spectroscopy -
Duration: 1 Oct 2007 → …


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