COMPOSITIONAL DEPENDENCE OF TRAPPED HOLE-CENTERS IN GAMMA-IRRADIATED CALCIUM ALUMINOSILICATE GLASSES

The electron spin resonance (ESR) spectra of a series of gamma-irradiated calcium aluminosilicate glasses with compositions CaO/Al2O3 = 1.50 and 0-80 mol% SiO2 have been measured at 9.3 GHz. The ESR spectra have been analyzed using spin-Hamiltonian parameters previously attributed to aluminum- and silicon-associated hole centers. Defect concentrations calculated from computer lineshape simulations based on the spin-Hamiltonian parameters are analyzed in terms of proposed defect precursor structures and a simple tetrahedral coordination model.