1.1 Evaluation of Test Procedures for Accelerated Photochemical Aging of Museum and Archival Materials

Carnegie Mellon Research Institute
Robert L. Feller
Mary Curran
C. W. Bailie
Val Colaluca
John Bogard
Period of Activity: 6/85 to 6/94

Project Abstract
Never before has accelerated photochemical aging of museum and archival materials been evaluated as thoroughly as in this research package. Regions of the visible and ultraviolet spectrum have been investigated for reactions involving yellowing and bleaching, (cellulose and wool); chain-breaking and cross-linking (Elvacite and poly[vinyl butyral]), and effects on fading of temperature and relative humidity.

Primary Publications
Feller, R. L., "Some Factors to be Considered in Accelerated Aging Tests," Preprints, The American Institute for Conservation of Historic and Artistic Works Annual Meeting, Vancouver, British Columbia, Canada, May 20-24 1987, pp. 56-67.

ABSTRACT-Factors to be considered in designing, executing, and interpreting accelerated aging tests are reviewed such as the selection of properties to be monitored, determination of acceptable limits of change, and method of plotting the changes versus time.

Feller, R. L., and M. Wilt, Accelerated Aging: Photochemical and Thermal Aspects, Research in Conservation, N 4, The Getty Conservation Institute, November 1994.

ABSTRACT-This handbook is a reference work on the theory and principles of carrying out accelerated aging tests. The main emphasis is on photochemical aging although thermal aging has also been addressed to a limited extent. Included subjects are the differences and problems in measuring chemical vs. physical change; the stages of deterioration; classes of durability; influence of wavelength; and the development between photolysis and photo-activation. Other sections include the practical aspects of carrying out such experiments, light sources, monochromator conditions, temperature and humidity, and experimental strategies.

Secondary Publications
Lee, S. B., J. Bogaard, and R. L. Feller, Damaging Effects of Exposure of Paper to Visible and Near-Ultraviolet Radiation, American Chemical Society Meeting, Division of Cellulose, Paper, and Textiles, Los Angeles, California, September 26-29, 1988.

ABSTRACT-Little data have been available concerning the loss of DP or increase in the degree of oxidation of cellulose during exposure to the visible and near-ultraviolet radiation emitted by ordinary "daylight" fluorescent lamps under moderate conditions of temperature and humidity, both during exposure and during subsequent thermal degradation. The present investigation, involving papers of little or no lignin content-an unbleached and bleached kraft pulp as well as filter paper-revealed moderate immediate effects of exposure and sensitization towards subsequent thermal degradation. Exposure under an ultraviolet filter noticeably reduced, but did not prevent, photochemical damage both during exposure and during subsequent aging of 50% RH and 90 C. Continuous exposures of 800,000 to 1,300,000 footcandle hours were involved.