Glassy inhomogeneities in oxide glasses represent one of the serious constraints of industrial glass production quality. Terms such as cord, striae and knots are used to describe such as inhomogeneities. In all cases, these represent regions of the glass which differ in composition from the surrounding matrix. The origins of such vitreous defects are manifold, e.g. batch contaminants, evaporation of volatile species, and refractory corrosion. The most evident problem posed by such glassy inhomogeneities resides in decreasing of the optical quality of glass products. Routinely, the chemical composition of knots is followed by EDS analysis. The obtained results are commonly evaluated qualitatively, i.e. the enhanced/decreased content of particular oxides/elements is followed. This paper deals with the application of advanced statistical methods for analysis of the chemical composition of a set of knots. The obtained results are straightforwardly related to refractory corrosion.
