The study of change in chemical conpositious of ancient glasses found in Eastern Asia.

研究在日本发现的古代玻璃的化学成分的变化，并将所得结果与中国和韩国的结果进行比较，是了解这些外国对日本玻璃生产技术影响的重要课题之一。玻璃样品（主要为玻璃微珠）采集自日本约50个考古遗址，时间跨度为公元前2世纪至公元8世纪末。对800多个玻璃样品的定量分析主要采用FP法微聚焦能量色散x射线荧光光谱法。此外，还采用电感耦合等离子体发射光谱法和原子吸收光谱法对部分样品进行了分析。腐蚀产物和风化表面层的玻璃样品初步清除了小检测区域进行分析。测定了在日本发现的一些玻璃的铅同位素比值。与过去在中国和韩国生产的玻璃或铅矿的数据进行了交叉验证。结果表明：1)公元前2世纪至公元3世纪的玻璃体系为k22o - sio_2、PbO-BaO-SiO_2和PbO-SiO_2。公元3世纪后期以后，出现了Na_2-CaO-SiO_2和Na_2O-Al_2O_3-CaO-SiO_2两种钠石灰玻璃体系，而铅玻璃则消失了。PbO-SiO_2体系在6世纪后期重新出现，并首次在日本生产。2)在日本首次发现的铅玻璃生产现场，出土了许多玻璃生产遗迹（可追溯至7世纪末）。我们的分析结果表明，这些玻璃是日本生产的第一批铅玻璃。

The study of the change in chemical compositions of ancient glasses found in Japan as well as the comparison of the obtained results with that of China and Korea is one of the important subjects to understand the influence of these foreign countries on Japanese glass-producing technique.The glass samples (mainly glass beads) were collected from about fifty archaeological sites in Japan, covering periods from 2nd century B.C.to the end of the 8th century A.D.The quantitative analysis of more than eight hundred glass samples were mainly performed by using a micro-focused energy dispersive X-ray fluorescence spectrometry with FP method. Besides, the inductive coupled plasma emission spectrometry and the atomic absorption spectrometry were also used for some samples.The corrosion products and the weathering surface layrs of glass samples were preliminary removed from the small examining area for the analysis.The lead isotope ratio of some glasses found in Japan were also measured. The data have been cross-checked with that of glasses or lead ores in China and Korea, known to have been produced in the past.Our results clarified the following facts :1) The distinctive glass systems at periods from ca.2nd century B.C.to the 3rd century A.D.were K_2O-SiO_2, PbO-BaO-SiO_2 and PbO-SiO_2. Two systems of soda-lime glass (Na_2-CaO-SiO_2 and Na_2O-Al_2O_3-CaO-SiO_2) appeared after the late 3rd century A.D., whereas two systems of before-mentioned lead glass disappeared. The PbO-SiO_2 system reappeared since the late 6th century, and produced in Japan for the first time.2) Many glass producing relics (dated as the end of 7th century) were excavated at the lead-glass producing site found for the first time in Japan. The results of our analysis showed that these glasses were the first lead-glass produced in Japan.