Raman spectroscopic determination of boroxol and borate ring contents in lead borate glasses

Glasses in the system xPbO·(100 – x)B2O3 (0 ≤ x ≤ 30 mol.%) were studied by Raman spectroscopy. The conversion of boroxol rings into borate rings containing one or two BO4 groups due to the transformation of threefold to fourfold coordinated boron with increasing content of lead oxide was determined from the intensities of the Raman peaks at 805 and 770 cm−1. Quantitative measurements were carried out on highly finished spherical samples to allow different reflection losses of the samples to be taken into account.