“…All types of colorizing metal oxides (Co, Cu, Fe, Mn,.) have characteristic absorption bands between 380 and 780 nm (Bamford, 1977;Green and Hart, 1987;Meulebroeck et al, 2010a;Mirti et al, 2000;Schreurs and Brill, 1984;Weyl, 1959). The spectral position of the absorption band depends mainly on the applied chromophore with small variations depending on the overall glass structure (Ceglia Fig.…”