Preparation of red colored borosilicate glass containing reducing agent and colloidal copper useful for decoration, e.g. of church windows

摘要

Preparation of red colored borosilicate glass by:melting of material containing (weight %):SiO2 (65.85), B2O3 (7-20), K2O (0-12), ZrO2 (0-12), Na2O (0-8), Al2O3 (0-7), BaO (0-5), TiO2 (0-6), Li2O, ZnO, MgO, CaO (all 0-2), CeO2 (0-1), remainder F, with Cu salt and/or Cu oxide as coloring and Sn salt and/or Sn oxide as anti-reduction, melt clarifying, addition of reducing agent, adjustment of temperature to 500-800 [deg] C for a time long enough to form colloidal Cu in the glass.