| Popis: |
Emanation thermal analysis (ETA) was used for characterization of the thermal behaviour of a borosilicate glass, designed for the vitrification of hazardous waste. Changes of release rate of radon atoms from the glass sample were measured continuously during heating in an air flow from 20 to 1000°C. Annealing of surface roughness, cracks and technological defects was indicated in the temperature range of 275–400°C by a decrease of radon release rate. A decrease of viscosity of the glass sample (in the proximity of the glass transition temperature, Tg) was indicated by the increase of the radon release rate starting at 430°C, whereas the decrease in the radon release rate starting, at 600°C, corresponded to the glass softening. Mathematical modelling was used for the description of the kinetics of radon release from the labelled glass sample and for the simulation of the ETA curve. Good agreement between the experimental data and the results of mathematical modelling of the ETA curve was found. |
