Epoxy polymer Hxtal NYL-1™ used in restoration and conservation: Irradiation with short and long wavelengths and study of photo-oxidation by FT–IR spectroscopy

Hxtal NYL-1™ is an epoxy adhesive designed especially for glass restoration and conservation, which however is used today on marble, wood, ivory and much more; it can also be colored or filled to match porcelain. This epoxy system is claimed by the manufacturers to have excellent photostability. The present study aimed at the estimation of its photostability under irradiation with light of λ = 254 nm or λ > 300 nm in the presence of oxygen (air) for a certain period of time towards samples cured at different temperatures. The changes of chemical structure caused by the irradiation of samples were studied by FT–IR spectroscopy. The general conclusion of this study is that the best temperature for curing of Hxtal NYL-1™ is that of 25 °C and that irradiation even with light λ > 300 nm must be avoided because may cause photo-oxidative reactions.