The Annealing Of Flat Glass

To begin with the author shows that density is the physical property which best characterises the structural state of the glass; he then determines as a function of the temps in the transformation range, the curves of equilibrium values of density of an ordinary crown glass and for each of these temps., the curves giving the variation of density and of birefringence as a function of time.// The author shows by typical examples how it may be dangerous to take into consideration in the use of glass only its residual birefringence apart from its degree of stabilisation as indicated by density.