Detection of the Glass Transition of Polymers Used in Art and Art-Conservation Using Raman Spectroscopy

Abstract

In this work Raman spectroscopy was employed for the detection of the glass transition temperatures (Tg) of some thermoplastic polymers and natural terpenoid resins. In particular, our attention was focused on evaluating the Tg of polystyrene and colophony. The measurements returned Tg values in accordance with those reported in the literature obtained using the DSC technique, thus confirming the reliability of the approach proposed herein. Further studies will be focused on the evaluation of Tg temperature changes depending on materials treatments and ageing.

Warm white LED lighting in museums: Ageing effects on terpenoid resins assessed through Raman spectroscopy and chemometrics

“…Moreover, in order to determine finely whether the intensity decrease is also associated with a frequency shift of the Raman bands during ageing, weighted averages were calculated for specific Raman bands in both the CH bending and C═C stretching regions in order to detect any minimal change in the molecular structure. This approach provides a sort of “centre of mass” of the selected Raman bands providing more repeatable and reliable determination of the band centre with respect to the usual peak fitting approach . Figures a and b show respectively the weighted averages of the peaks position between 1,400 and 1,500 cm −1 of CH bending vibrational modes and between 1,550 and 1,750 cm −1 of the C═C stretching region as a function of the number of the Raman spectra acquired.…”