江戸時代に制作されたと伝えられる紫色のガラス器に用いられた材料

抄録

Materials for a purple glass bottle manufactured in the late Edo-era were studied. The design on this purple glass bottle is a potted flower. Infrared light images show light refraction at the flower and soil areas. There is a contrast between the petal and the rim in these images. These results indicate that different materials were used in these parts. UV-light fluorescence images show weak fluorescence at the leaves and the stem. The glass of this bottle contains Pb, Si, and K as the main components and minor components of Mn, Fe, Na, and Al, as revealed by SEM-EDS analysis. The glass composition is not homogeneous as a result of the manufacturing process. The Si species measured by XRF is SiO₂ and Pb is in the form of Pb₃O₄ according to X-ray diffraction measurement. Measurements of the decorated area indicate that Cu-Zn alloy is used in the area of the soil in the flowerpot, and SnO and SnO₂ are corrosion products that exist on the surface of Sn thin film. The peak at 390 nm on the reflection spectrum corresponds to the purple color of this glass bottle. The results of XAFS measurement reveal that the oxidation state of Mn is a mixture of +2 and +3, that of Fe is +3, and that of Pb is +2.