Estimation of Absorbed Photolytic Dosage and Quantum Yields Using UV-Vis and FTIR spectroscopies

Published

March 1, 2000

Author(s)

Jonathan W. Martin, Tinh Nguyen, E Byrd, N Embree

Abstract

An effective dosage model has been introduced for predicting the service life of polymeric materials exposed to UV light. The effective dosage model, which relates material damage through the apparent quantum yield, has a firm basis in the priciples of photochemistry. The primary inputs into this model are radiation dosage absorbed in the material and material damage, and the outputsare effective dosage and apparent quantum yield. Laboratory experiments were designed to provide data on these parameters over wide ranges of conditions to encompass those environments to which a coating is expected to be exposed in the field and to allow the effects of competing degradation reactions to be separated. UV visible spectroscopy and FTIR spectroscopy were used to measure absorbed dosage and damage in the coatings, respectively. Estimates of the absorbed dosage and apparent quantum yield were found to be very sensitive to initial UV-visible absorption of the coatings, coating degradation products, anomalous UV absorption of the substrate, spectral handling of infrared and UV-visible spectra, and the reproducibility of UV-visible and FTIR spectrometers.

Citation

Journal of the American Chemical Society

Volume

219

Issue

No. 141

Pub Type

Journals

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Local Download

Keywords

building technology, coatings, degradation, effective dosage, FTIR, polymer, quantum yield, UV spectroscopy

Citation

Martin, J. , Nguyen, T. , Byrd, E. and Embree, N. (2000), Estimation of Absorbed Photolytic Dosage and Quantum Yields Using UV-Vis and FTIR spectroscopies, Journal of the American Chemical Society, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=860234 (Accessed December 6, 2024)