ESR spectroscopy - an analytical tool for the glass industry

In the past, wet chemical methods have been developed for the quantitative analysis of polyvalent elements in glasses. The major disadvantage of these chemical methods is that all structural information is lost during analysi s. In addition, the analysis of species by wet chemical methods is unreliab le due to possible redox reactions during the decomposition process. Theref ore, the emphasis is on the physical methods which can directly detect spec ies in bulk glasses. Especially optical and ESR spectroscopy are suitable m ethods due to their wide range of applications and sensitivity. Concerning quantitative measurements, no comparison between ESR results and chemical a nalysis of species has been published so far. This work discusses the possi ble application of ESR spectroscopy in the glass industry by focussing on r outine interpretation, the correlation to chemical procedures and quantitat ive analysis. Results are presented and discussed for iron and chromium in packaging glasses. For example an excellent correlation was found between t he Fe3+ ESR signal and the chemically determined Fe3+ concentration in glas s.