Evaluation of the calorimetric glass transition of glasses and glass ceramics with respect to structural relaxation and dimensional stability

Investigation of the effect of coefficient of thermal expansion on prediction of refractive index of thermally formed glass lenses using FEM simulation

“…Thus the volume at a point after cooling, V c , is given by the following approximate relationship in Eq. (12):…”

“…Because β h , β c and the elastic strains are very small, by combining Eqs. (8a), (12), and (13), and ignoring the higher orders of β h , β c and the elastic strains, the volume change is given as:…”

“…where τ 0 = 1.68 × 10 − 46 s for P-SK57 glass [3], τ 0 = 5.76 × 10 − 54 s for P-LASF47 glass [3] and τ 0 = 8.75 × 10 − 36 s for BK7 glass [12]. …”

“…The temperature used in the simulation was based on measurements from sensors buried inside the molds, and was not the actual temperature at the surface of the glass plate. The important material properties of BK7 glass were summarized in Table 1 and Table 2 [12][13][14]. Based on the measured results [14], the liquid CTE for BK7 glass was determined to be 3.77 × 10 − 5 K − 1 .…”

The residual configurational entropy below the glass transition: Determination for two commercial optical glasses

“…Details of the DSC data analysis are described in [31,32]. The DSC used is of the heat-flux type (Setaram Multi-HTC 96, sensor head with S-thermocouples, cylindrical samples with 6 mm diameter and ca.…”