Effect of sulfates and nitrates of alkali-earth metals on gas content in glass

Glass fibres

“…This indicates that both OH groups and protons are involved in the formation of the chemical bond. It is found from comparison of the energy differences L1E1 = E~ -E~H for finishing agents (Table 1. 21) and L1E2 = EH -EOH for their absorption complexes with glass that they show a linear dependence, which is maintained in the case of absorption complexes of finishing agents with clusters containing aluminium-oxygen tetrahedra modified by sodium and magnesium. Thus modification of one of the Si -0 bonds of the finishing agent or glass fibre influences the energy of the chemical bond between them.…”

“…Reheated glass will behave differently according to its degree of gas saturation. There is a method of estimating the predisposition of a glass to gas extraction during reheating -it is based on measuring the temperature of the beginning of gas extraction (tf) from the glass when it is melted in vacuum at 1 x 10 4 Pa [21,29]. Studies of the effect of t f on fibre breakage in the remelt process have shown a correlation between these parameters ( Fig.…”

“…The solubility of these gases and that of water vapour sharply increase with the increase of oxygen in the glass melt. This is achieved in practice by adding oxygenextracting additives (nitrates, sodium sulphate) to the batch, especially in combination with arsenic trioxide and other oxides of different valencies [21,23,28]. The valency of these elements in the presence of oxygen increases and results in an increase in chemically bonded oxygen in the glass melt.…”

“…As the result of physical and chemical processes, which take place in the batch and glass melt at high temperatures, gases are formed, most of which escape from the glass melt, but a considerable number (20-40vol.%) remain [20][21][22]. The saturation of the glass melt with gases depends on the solubility of the gases, and in this case, if the HP, 5°3, O 2 and CO 2 content depends on chemical interactions with the glass melt, then N2 depends on its physical solubility.…”