Evaluation of the concentration of boroxol rings in vitreous B2O3 by the stochastic matrix method

A statistical model in which the stochastic matrix method is applied is used to find the fraction of boron atoms belonging to boroxol rings in a boron oxide (B2O3) glass. The method also enables one to evaluate the characteristic energies related to the formation of a single B-O-B unit in an oxygen bridge or in a boroxol ring. The qualitative behaviour of the heat capacity Cp(T) during the glass transition is reproduced, with the inflexion point at the temperature given by the experiment. The model also gives a reasonable qualitative prediction for a characteristic exponent ruling the growth of microclusters, which may in turn be related to the specific volume. (author)