Obserbation of SiO_2-Na_2O System Glass Forming Reaction : NaOH as the Source of Na

This paper is extention of previous papers. In previous papers, SiO_2-Na_2O system glass forming reactions were examined by mathematical statistics, i.e. Student test and relative decrease of volume. In this experiment, NaOH was used as the source of Na instead of Na_2CO_3. Mixture of SiO_2 particles and NaOH was heated in electrical furnace in constant temperature and time, then the products were washed with conc. HCl to remove NaOH. The diameters of SiO_2 particles and attacked SiO_2 particles were measured with microscope and statistical distribution of SiO_2 particle's diameters was obtained. Ensemble of SiO_2 particles was assumed to be population and that of attacked SiO_2 particles to be sample, then mathematical statistics was applied to data. The conclusions are as followings. 1) It is found that Student test and value of relative decrease of total volume are very convenient to observe SiO_2-Na_2O system glass forming reaction. 2) It is found that NaOH is more active than Na_2CO_3 in this reaction.