Determination of trace elements in ancient glasspieces and correlation with corrosion and devitrification

Differently corroded glass-pieces of Roman, mediaeval and baroque origin were inspected by light and electron microscopes and afterwards several impurities determined semi-quantitatively in the glass matrix and corrosion layers by neutron activation analysis. Sodium glasses contained in general less trace elements and proved to be more resistant against corrosion and devitrification than potassium glasses which showed a high content of foreign elements. In the intermediate layers between glass and corrosion products not only an increased number of impurities was detected, but also an enrichment factor of about 20 in comparison to the glass matrix was found. According to the observed relation between content of trace elements and degree of corrosion, impurities seem to deteriorate the long term stability of a glass matrix. Dedicated on the occasion of the 70th birthday of Prof. Dr. R. KIEFFER, University of Technology, Vienna.