DETECTION OF MULTIPLE BORON SITES IN GLASSES BY B-11 SATELLITE TRANSITION NUCLEAR-MAGNETIC-RESONANCE SPECTROSCOPY

The magic-angle spinning sidebands of the satellite transition (ST, m = +/-3/2 <----> +/-1/2) for B-11 nuclear magnetic resonance ((11) B ST spectroscopy) have been used to detect multiple boron sites in Na2O-B 2O3-SiO2 glasses. The experimental details and data analysis are descr ibed, how multiple BO4 and BO3 units can be distinguished using standa rd magic-angle spinning. For a 16Na(2)O-30B(2)O(3)-53.9SiO(2) glass (0 .1 MnO) two BO4 units with chemical shifts of -2.5 and 0 ppm were foun d which differ considerably in their quadrupole interaction. Besides t his we found three different BO3 units with approximate chemical shift s of 17, 15, and 19 ppm. The results are compared with earlier measure ments.