EPR and Kinetic Studies of Hydrogen Centers in Aluminoborate Glasses

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Abstract
Barium aluminoborate glasses containing hydrogen as an impurity, irradiated at 77 K with X rays, show the characteristic doublet of atomic hydrogen in the EPR spectra when measured at Thfs constant of the Hoi center is smaller than that of free atomic hydrogen, indicating that the attractive van der Waals interaction is more important than the repulsive Pauli exclusion forces in that glassy matrix. It is suggested on the basis of isochronal and isothermal annealing experiments that there are at least three different sites for hydrogen, each one contributing with Ist‐order decay kinetics. The activation energies found in 30 mol% BaO, 60 B2O3, 10 Al2O3 glass are, respectively, equal to E1=(0.5±0.1), E2=(0.24±0.03), and E3=(0.16±0.03)×lO−19 J.