Theoretical thermo-optical patterns relevant to glass crystallisation

Abstract

Mie computations are performed to evaluate light scattering on the virtual microstructures relevant to lithium disilicate glass internal crystallisation. The computations are expressed in the form of optical transmission (OT) patterns evolved on a scale of growing lithium disilicate crystals. Input data include the crystals number density, their size, the wavelength of the incident electromagnetic radiation, the indices of refraction of the lithium disilicate glassy and crystalline phases and the thickness of the virtual glass slab. In the computations, the spherical shape of crystals and their random distribution are assumed. The results reveal the quantitative effects of individual input data constants on the overall course of the computed OT patterns. They also relate the computed OT data magnitudes to the corresponding glass crystallinity (α). In addition, they point to singular combinations of the input data constants defining the conditions under which the OT data could potentially stand for the kinetically important α data. Finally, the results aid better recognition of some fundamental as well as practical properties of the optical thermal methods based on the optical transmission measurements.

Computed optical transmission records: An effect of dense-medium phase function as an approximate description of multiple light scattering

“…As already mentioned [2], the SLS OT curves conform well to an equation of the descending (reverse) sigmoidal of the form:…”

“…The signals from neighboring particles might be phased, thus resulting in constructive or destructive interferences. Therefore the underlying physics of this phenomenon differs from that used in our previous works [1,2].…”

“…(2)(3)(4). It is usually convenient to relate the number concentration of scattering particles with the degree of conversion (or degree of crystallinity) α.…”

“…In our previous work we have accessed the computation of light scattering by proposed physical structures relevant to crystallization of glass [1,2]. The attenuation of a light beam incident perpendicularly to a glass slab was expressed in terms of the optical transmission (OT).…”