# Spectroscopic and Microscopic Characterization of Flashed Glasses from Stained Glass Windows
## 3 Results and Discussion
### Chemical Characterization  
The chemical composition of the flashed glasses was determined using FESEM-EDS, UV-Vis-IR spectroscopy, LIBS, and LIF. 2.1 Field Emission Scanning Electron Microscopy/Energy-Dispersive X-ray Spectroscopy and UV-Vis-IR Spectroscopy  
The FESEM-EDS analysis of the cross-sections revealed that all the base glasses are soda-line silicate glasses with similar chemical compositions (Table 2). The content of silica varied between 63 and 72 wt.%, sodium oxide between 14 and 20 wt.%, and calcium between 9 and 14 wt.%. The base glass of the Green2 sample was slightly different, with an extra amount of around 9 wt.% of BaO. This oxide is sometimes used in substitution of PbO as it increases the refraction index of the glass and, therefore, its shine, and additionally avoids unwanted devitrification [45]. Regarding the colored layers, three samples (Pink1, Green1, and Green3) display a high content of lead. This element is commonly used to reduce the melting point of the \begin{table}
\begin{tabular}{c c c c c c c c c c c c c c c c} \hline \hline  & **Na\({}_{\text{2}}\)O** & **MgO** & **SiO\({}_{\text{2}}\)** & **K\({}_{\text{3}}\)O** & **CaO** & **TiO\({}_{\text{2}}\)** & **Cr\({}_{\text{2}}\)O\({}_{\text{3}}\)** & **MnO** & **Fe\({}_{\text{2}}\)O\({}_{\text{3}}\)** & **CoO** & **NiO** & **CuO** & **ZnO** & **BaO** & **PbO** \\ \hline Pink1 & CL & 0.9 & - & 29.1 & 5.5 & - & - & - & - & - & - & - & - & - & 3.7 & 60.8 \\ \cline{2-13}  & BG & 14.5 & - & 71.3 & 1.1 & 13.1 & - & - & - & - & - & - & - & - & - & - \\ \[PERSON] & CL & 10.7 & - & 71.6 & 5.1 & 11.5 & - & - & - & - & - & - & 1.0 & - & - \\ \cline{2-13}  & BG & 15.0 & - & 69.6 & 1.4 & 14.0 & - & - & - & - & - & - & - & - & - & - \\ \[PERSON] & CL & 8.7 & - & 48.9 & 2.3 & 9.3 & - & 16.7 & - & 14.1 & - & - & - & - & - & - \\ \cline{2-13}  & BG & 15.3 & - & 70.4 & 0.8 & 13.5 & - & - & - & - & - & - & - & - & - & - \\ \[PERSON] & CL & 11.8 & - & 72.4 & 5.4 & 9.7 & - & - & - & - & - & - & 0.7 & - & - & - \\ \cline{2-13}  & BG & 15.3 & 0.8 & 70.4 & 0.7 & 12.6 & - & - & - & - & - & - & - & - & - & - \\ \hline Blue1 & CL & 14.9 & - & 70.7 & 1.6 & 10.9 & - & - & - & - & - & - & 1.9 & - & - & - \\ \cline{2-13}  & BG & 17.0 & - & 70.3 & 1.2 & 11.5 & - & - & - & - & - & - & - & - & - & - \\ \hline Blue2 & CL & 15.0 & 0.6 & 69.8 & 2.1 & 10.6 & - & - & - & - & 1.8 & - & - & - & - & - \\ \cline{2-13}  & BG & 17.6 & 0.6 & 70.4 & 0.6 & 10.8 & - & - & - & - & - & - & - & - & - & - \\ \hline Blue3 & CL & 16.6 & 1.2 & 64.3 & 1.1 & 8.9 & - & - & - & - & 6.7 & - & - & 1.1 & - & - \\ \cline{2-13}  & BG & 19.0 & 1.6 & 69.0 & 0.4 & 9.9 & - & - & - & - & - & - & - & - & - & - \\ \hline Black & CL & 12.9 & 0.6 & 60.0 & 1.6 & 8.9 & - & - & 12.8 & - & 1.2 & 1.9 & - & - & - & - \\ \cline{2-13}  & BG & 17.1 & - & 71.9 & 0.5 & 10.5 & - & - & - & - & - & - & - & - & - & - \\ \hline Green1 & CL & 2.5 & - & 46.6 & 9.4 & - & 4.4 & 1.5 & - & - & - & - & - & - & - & 35.6 \\ \cline{2-13}  & BG & 18.3 & 1.8 & 70.4 & - & 9.5 & - & - & - & - & - & - & - & - & - & - \\ \hline Green2 & CL & 11.7 & 1.2 & 55.5 & 0.4 & 6.6 & - & - & - & 6.3 & - & - & 6.7 & - & 11.5 & - \\ \cline{2-13}  & BG & 16.7 & 1.4 & 63.1 & 0.4 & 9.1 & - & - & - & - & - & - & - & 9.3 & - \\ \hline Green3 & CL & 2.3 & - & 44.4 & 10.5 & - & - & 1.4 & - & - & - & - & 3.9 & - & - & 37.4 \\ \cline{2-13}  & BG & 19.3 & 1.9 & 68.2 & 0.4 & 10.2 & - & - & - & - & - & - & - & - & - \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Chemical composition (wt.%) of the surface-colored layer and of the base glass analyzed by FESEM-EDS. CL: Colored layer, BG: Base glass. surface layer, favoring its adherence to the base glass. These three samples, together with the Black one, are those in which the colored layer showed a clear hue under FESEM observation (Figure 3), an effect attributed to the high content of heavy elements such as lead. About the colorant agents, most of the surface layers showed a relatively high concentration of chromophores.