Determination of the mesostructure of lead borate glasses using laser photoionization mass spectroscopy

We have investigated the structure of lead borate glasses up to high lead c ontents using a high-resolution reflectron time-of-flight mass spectrometer . The glasses showed the repeatable presence of intermediate-range units, w hich varied in relative abundance depending on composition. This direct mea surement of the network showed a high abundance of (B3O5) and (PbB3O6) grou ps, which are likely to arise from metaborate rings, as well as the rise of ortho- and pyroborate units. Smaller quantities of entire diborate units ( B4O9, with added lead and boron atoms for charge compensation) were also ob served. (C) 2000 American Institute of Physics. [S0003-6951(00)02601-2].