Table 1.

Chemical composition of glazes (w%) and stoichiometry of Seger for SG4 sample

	SG1 parent glaze	SG2 calcic	SG3 aluminous	SG4 calcic-aluminous
SiO2	50	50	50	50
CaO	-	18	-	18
K2O	4	4	4	4
Al2O3	-	-	8	8
ZnO	12	12	12	12
B2O3	8	8	8	8

$\begin{array}{c}\mathrm{SG}4\left({\mathrm{SEGER}}^{\prime }\mathrm{s}\mathrm{FORMULA}\right)\hfill \\ \begin{array}{ccc}\hfill \left(\begin{array}{c}0.22{\mathrm{K}}_2\mathrm{O}\hfill \\ 0.78\mathrm{ZnO}\hfill \end{array}\right\}\hfill & \hfill 0.39{\mathrm{Al}}_2{\mathrm{O}}_3\hfill & \hfill \left\{\begin{array}{c}6.27{\mathrm{SiO}}_2\hfill \\ 0.58{\mathrm{B}}_2{\mathrm{O}}_3.\hfill \end{array}\right)\hfill \end{array}\hfill \end{array}$