Expansivity and the Structure of the Soda Lime Glasses,

The structure of sodium-calcium glasses was discussed on the basis of their thermal expansion. The low, expansion coefficient of SiO2 glass compared with the expansion coefficient of quartz and the isotropy of SiO2 glass are contradictory with the Lebediev crystallite tyeory but in agreement with the net theory of Zachariasen, which also explains the higher expansion of Na2O-SiO2 glasses where, as a result of Na2O introduction, the ring is broken, and the expansion increases proportionally to the Na2O content. Author