Caustic Patterns Associated With Melt Zones in Solidified Glass Samples - Part II: Asymmetric Cases

In the present study, we demonstrate how deviations from rotational symmetry in the melt zone give rise to asymmetries in the resulting caustic pattern. In Ref. 1, rotationally symmetric profiles of melt zones were generated by averaging measurements of data taken from solidified melt zone samples. These data provided symmetrically idealized data sets for the study of the two principal types of caustics as functions of the rate of change in the cross section. Changes in the maximum rate of change in the cross section were simulated by scaling* the data sets, and the analysis was carried out using the algorithms developed earlier in Ref. 2. These algorithms describe families of 2- and 3-intercept caustics as shown in Fig. la, where the scale factor is unity. The incident angle, j3, for an axial light ray at the inflection point, I, is 52.9 degrees on both sides of the cross section. However, in Ref. 2 it was shown that the samples were usually asymmetric, resulting in pronounced asymmetric caustic patterns, especially when the caustic rays emerged nearly tangent to the surface. * That is, by scaling the axial and transverse data values differently with the scale factor, SF = (axial scale)/(transverse scale). 3227