134 MATERIAL ENGINEERING, STRUCTURAL STUDIES, DIAGNOSTICS ULTRAVIOLET BLUE FLUORESCENCE OF CENTRAL EUROPEAN BAROQUE GLASS (FURTHER RESULTS) Jerzy Kunicki-Goldfinger, Joachim Kierzek, Piotr Dzierżanowski1/ 1/ Faculty of Geology, Warsaw University, Poland About 1200 colourless glass vessels originated Analyses by wavelength dispersive spectrometry mainly from central European areas and dated to in the EPMA system were carried out using 17th and 18th centuries were analyzed by the use Cameca SX-100 at the Electron Microprobe Labo- of energy dispersive X-ray fluorescence (EDXRF) ratory, Faculty of Geology, Warsaw University. analysis and examined under UV-C radiation. Standards were oxides and minerals. Corning B, These observations were carried out to distinguish C, D, and NIST 610, 612, among others, were used the items that show blue fluorescence, which is as secondary standards. associated with the presence of lead in glass. The The obtained results have confirmed that blue colour of fluorescence was determined with the fluorescence of baroque central European vessel naked eye. Also, small samples were taken from glass is connected to the presence of lead in glass. the 88 examined objects. They were analyzed by There is no border PbO concentration that cause the use of electron probe microanalysis (EPMA). the phenomenon. The PbO concentration even The project constitutes a continuation of our below 0.2% can cause the bright blue fluorescence. previous paper [1]. On the other hand, in this range slightly below A band with the dominant line of 253.7 nm 0.5% of PbO, a few examined glasses did not show (usually denoted as UV-C) was applied. Commer- the fluorescence at all. These vessels are attributed cially available sources of the UV-C radiation were to unknown Polish and/or Russian factories run used (two low pressure TUV 15 V mercury lamps, by the end of the 18th century. manufactured by Philips). They were installed in a The presence or absence of blue fluorescence special chamber for safe observation of the phe- does not seem to depend on the concentration of nomenon. The total radiation intensity in the Mn and Fe, thought the relative ratios of Pb, Mn chamber amounted to 8.257x10–4 W/cm2 (for the and Fe influence the changes of glass fluorescence wavelength range of 200-398 nm), with a single under UV-C in the case of such small lead con- dominant peak of 2.503x10–4 W/cm2 for a wave- centrations. length of 254 nm. When the PbO content is higher (over 0.5%), Energy dispersive X-ray fluorescence was used glass shows this fluorescence independently of the in a surface manner. The 109Cd and 241Am radio- kind of glass matrix composition. There is one ex- isotope annular sources were applied to excite the ception found and it concerns a few vessels attrib- elements in the glass. X-ray spectra were measured uted to Zechlin (or Potsdam), Brandenburgia using Si(Li) and a planar HPGe detectors. The live (Fig.1). It should be underlined that not all glasses time of the measurements was 600 s. The analyzed from this glass centre behave in this way; other

Fig.1. Triangular diagrams for the variables Pb, Mn, and Fe. The variables have been transformed in such a way that the sum of their values is constant for each case. area of glass amounted to approximately 2 cm2. examples also containing lead show the blue fluor- No quantitative chemical analysis was carried out escence. We do not know the reason of it. by the use of EDXRF. Only PbO contents were es- Three groups of leaded central European glass, timated. which show blue fluorescence under UV-C radia- NUCLEAR TECHNOLOGIES AND METHODS 135 by the use of EPMA [wt%]. <0.4. 5 O 2 Table. Chemical composition of 21 glasses analyzed < – below detection limit. For all samples: P 136 MATERIAL ENGINEERING, STRUCTURAL STUDIES, DIAGNOSTICS tion, have been distinguished (tentatively marked highest PbO concentration reaching c. 2%. “B” is A, B, and C) (Fig.2). “A” is white (chalk) glass with crystal glass. The PbO content did not exceed 6%. “C” is also crystal glass, but with the PbO content over 6%. These groups differ from one another in the chemical composition as a consequence of the application of determined recipes and raw ma- terials. Chemical composition of 21 glasses with the highest PbO concentration analyzed by the use of EPMA (in wt%) are presented in Table. The items have been sorted according to their lead content and the presence of blue colour of their fluorescence is indicated. The PbO level in the remaining 67 glasses, also examined by the use of EPMA, re- mains below 0.04% and they did not show blue fluorescence. It can be seen that the glasses with PbO content over about 0.2-0.3% show this distinct blue fluorescence. Though, there are two excep- tions and both vessels were produced in Zechlin. According to our previously published results, we can now divide leaded crystal central European glass from the 18th century into two groups, B and C. The further conclusion is that all glasses that belong to group C showed blue fluorescence. Among the glasses from group B, we have found a few exceptions. We have also found a few examples with very low lead content (or with its concentration below the detection limit) that exhibit weak pale-blue fluorescence. This phenomenon is caused probably by the presence of other kind of fluorescent centre in glass than lead. Spectroscopy seems to be undoubtedly needed for further studies on this phenomenon. The project has been carried out at the Institute of Nuclear Chemistry and Technology in Warsaw within the frameworks of a few separated projects since 1998. The following museums made the vessels avail- able for examination: the National Museums (Gdańsk, Cracow, Poznań, Warsaw, Wrocław), the Royal Castle in Warsaw, the Wawel State Art Col- lection, the Czartoryski Museum and the Jagiellon- ian University Museum (Cracow), the District Mu- seums (Jelenia Góra, Rzeszów, Tarnów), the Łań- cut Castle Museum, Museum in Nieborów and Arkadia, the Museum-Palace in Wilanów, the His- torical Museum of Warsaw and private collectors. Fig.2. The scatter plots for PbO [wt%] and, respectively References Rb, Y and Zr. Rb, Y and Zr contents are expressed in arbitrary units. Three groups of leaded glass have [1]. Kunicki-Goldfinger J.J., Kierzek J.: Glass Technol., been distinguished. 43C, 111-113 (2002).

LATE 17th CENTURY GLASS VESSELS FROM EILAND – TECHNOLOGICAL APPROACH Jerzy Kunicki-Goldfinger, Martin Mádl1/, Piotr Dzierżanowski2/ 1/ National Museum & Institute of Art History, Academy of Sciences of Czech Republic, Prague, Czech Republic 2/ Faculty of Geology, Warsaw University, Poland

We know relatively little about glass production ous technologies and manufacturing processes that in the second half of the 17th century, when vari- would later become commonplace were still being