is an inorganic product of fusion that is cooled and solidified without noticeably crystallising (“solidified melt”).
Thin filaments (diameter less than 100 µm) made of glass. They are drawn from the melt and because of the extreme chilling conditions prevailing during their production their properties differ from those of compact glass. In particular, their tensile strength is very high.
Glass, optical (Optical glass)
Optical glass is a clear glass with specified values of the refractive indices. It should be as free as possible from bubbles, knots, stones, striae, and stress.