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  • 1.
    Druenert, F.
    et al.
    Univ Jena, Germany.
    Blanz, M.
    Univ Jena, Germany;Univ Highlands & Isl, UK.
    Pollok, K.
    Univ Jena, Germany.
    Pan, Z.
    Univ Jena, Germany.
    Wondraczek, L.
    Univ Jena, Germany.
    Möncke, Doris
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology. Natl Hellen Res Fdn, Greece.
    Copper-based opaque red glasses - Understanding the colouring mechanism of copper nanoparticles in archaeological glass samples2018In: Optical materials (Amsterdam), ISSN 0925-3467, E-ISSN 1873-1252, Vol. 76, p. 375-381Article in journal (Refereed)
    Abstract [en]

    Red opaque glasses of two different sites in central Germany, a medieval glassworks in Glashutten, Taunus Mountains, and an early modern glassworks in Wieda, Harz Mountains, were analysed with regard to their optical appearance. By scanning electron microscopy and X-ray diffraction, metallic copper nanoparticles were identified as a conspicuous constituent in these glasses. In addition, similar opaque red glasses were reproduced in the laboratory in order to better understand the manufacturing process. Detailed analysis of the optical scattering was conducted in order to evaluate the role of Cu-0 nanoparticles in the colouring mechanism relative to other possible reasons of colouration. We find clear differences between the possible contributions of Cu2O (cuprite) particles and metallic copper (Cu-0) nanoparticles. Through simulated backscattering spectra we were able to calculate an average copper particle radius in the archaeological glass samples resulting in a value of up to 95 nm, which matches well the results of SEM investigation (minimum 65 nm). Using the methods we applied in this study, it becomes possible to reconstruct various processing conditions as they were applied in medieval manufacture of these particular materials. (C) 2018 Elsevier B.V. All rights reserved.

  • 2.
    Druenert, Ferdinand
    et al.
    Univ Jena, Germany.
    Palamara, Eleni
    Univ Peloponnese, Greece.
    Zacharias, Nikolaos
    Univ Peloponnese, Greece.
    Wondraczek, Lothar
    Univ Jena, Germany.
    Möncke, Doris
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology. Natl Hellen Res Fdn, Greece.
    Ancient Roman nano-technology: Insight into the manufacture of mosaic tesserae opacified by calcium antimonate2018In: Journal of the European Ceramic Society, ISSN 0955-2219, E-ISSN 1873-619X, Vol. 38, no 14, p. 4799-4805Article in journal (Refereed)
    Abstract [en]

    Opaque mosaic glass tesserae containing calcium antimonates from Ancient Messene, Greece (1st-4th century CE) were investigated by scanning electron microscopy, Raman spectroscopy and X-ray diffraction. Both trigonal CaSb2O6 and cubic Ca2Sb2O2, with crystallite diameters below 1 pm, were identified as opacifying agents. To better understand ancient technologies, we prepared model glasses that were opacified by crystallisation via a secondary heat treatment, by direct crystallisation during the melting process, or by the addition of pre-reacted calcium antimonate to a base glass. We found that direct crystallisation replicated the antique glass artefacts most accurately. We demonstrated that 0.2 wt% of nucleating agents like TiO2 and SnO2 already exert significant influence on the crystallisation behaviour of calcium antimonates. Secondary scattering centres such as silica and carbonates contribute to the optical appearance. Concurrently, we reproduced opaque white glass ceramics in a reconstructed, wood-fired, Roman-type glass furnace built by Wiesenberg (2014).

  • 3.
    Efthimiopoulos, I.
    et al.
    Natl Hellen Res Fdn, Greece;Deutsch GeoForschungsZentrum GFZ, Germany.
    Palles, D.
    Natl Hellen Res Fdn, Greece.
    Richter, S.
    Friedrich Schiller Univ Jena, Germany;TRUMPF Lasertech GmbH, Germany.
    Hoppe, U.
    Univ Rostock, Germany.
    Möncke, Doris
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology. Natl Hellen Res Fdn, Greece.
    Wondraczek, L.
    Friedrich Schiller Univ Jena, Germany;Fraunhofer Inst Appl Opt & Precis Engn, Germany.
    Nolte, S.
    Friedrich Schiller Univ Jena, Germany;Fraunhofer Inst Appl Opt & Precis Engn, Germany.
    Kamitsos, E. I.
    Natl Hellen Res Fdn, Greece.
    Femtosecond laser-induced transformations in ultra-low expansion glass: Microstructure and local density variations by vibrational spectroscopy2018In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 123, no 23, article id 233105Article in journal (Refereed)
    Abstract [en]

    We report X-ray diffraction, resonance Raman, and infrared (IR) results on pristine ultra-low expansion (ULE) glass, a binary titanosilicate glass with 5.67 mol. % TiO2. ULE processing by femtosecond (fs) laser radiation leads to nanograting writing and photo-darkening for imaging and data storage. We investigate here the vibrational/structural changes induced by fs laser irradiation of ULE at 515 nm. Optical imaging revealed the formation of micro-cavities, and Raman mapping showed molecular oxygen trapped in such cavities of laser-irradiated ULE glass. While titanium in the pristine glass was found predominantly in tetrahedral Ti4+ sites highly dispersed in the silicate matrix, Raman and IR reflectance spectroscopy on laser-irradiated ULE indicated the formation of Ti3+ sites; Ti3+ octahedral sites are formed in the shells of cavities and aggregate in amorphous Ti2O3-type clusters, while the glass around and below cavities contains Ti3+ tetrahedral sites dispersed in the silicate network. Laser-processed ULE glass was found to also exhibit local restructuring of the silicate matrix. Shifts of the strong IR band at about 1080-1100 cm(-1) were translated into changes of the average Si-O-Si bond angle in the laser-transformed areas and found to reflect local density variations; the average local density increases relative to silica glass up to about 8% in the shells of micro-cavities and decreases by about 0.5% in the surrounding material. Chemical processes were proposed to account for photo-darkening and the local structural transformation effect in the probed areas of the fs laser-processed ULE glasses. Published by AIP Publishing.

  • 4.
    Grund Bäck, Lina
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology. RISE, Sweden.
    Ali, Sharafat
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Karlsson, Stefan
    RISE, Sweden.
    Möncke, Doris
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology. National Hellenic Research Foundation, Greece.
    Kamitsos, Efstratios
    National Hellenic Research Foundation, Greece.
    Jonson, Bo
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Mixed alkali/alkaline earth‐silicate glasses: Physical properties and structure by vibrational spectroscopy2019In: International Journal of Applied Glass Science, ISSN 2041-1286, Vol. 10, no 3, p. 349-362Article in journal (Refereed)
    Abstract [en]

    In this article, we investigate the correlation of selected physical properties with structural changes in quaternary mixed modifier alkali/alkaline earth oxide silicate glass systems, focusing either on the mixed alkali effect [(20−x)Na2O–xK2O–10CaO–70SiO2 (x = 0, 5, 10, 15, 20)] or on the mixed alkaline earth effect [20Na2O–(10−y)CaO–yBaO–70SiO2 (y = 0, 5, 10)]. A maximum microhardness and packing density, as well as a minimum glass transition temperature were observed for mixed alkali glasses. The mixed alkaline earth glasses do not exhibit any clear extrema in any of the properties studied. The hardness and glass transition temperature decreases, while the density and molar volume increases with increasing BaO content. Raman spectroscopy showed an increase in the Q3 group compared to the Q2 and Q4 groups as the high field strength ions Na+ or Ca2+ are substituted by their low field strength analogs K+ or Ba2+. In the mixed alkali series, the high field strength ion Na+, seems to push the low field strength ion K+ into lower energy sites when present simultaneously, while such an effect is not apparent for the mixed alkaline earth glasses, where the far IR spectra of mixed glasses are equivalent to the weighted averages of the pure glasses.

  • 5.
    Möncke, Doris
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology. National Hellenic Research Foundation, Theoretical and Physical Chemistry Institute, Greece.
    Ali, Sharafat
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Wójcik, Natalia A.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology. Gdańsk University of Technology, Poland.
    Palles, Damitris
    National Hellenic Research Foundation, Theoretical and Physical Chemistry Institute, Greece.
    Kamitsos, Efstratios
    National Hellenic Research Foundation, Theoretical and Physical Chemistry Institute, Greece.
    Jonson, Bo
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    IR and Raman study of oxy-nitride glasses2018In: Presented at Glass and the Meeting of Minds  (SGT18), Cambridge, UK (2nd -5th September 2018), 2018, p. 54-Conference paper (Refereed)
  • 6.
    Möncke, Doris
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology. Fed Univ Sao Carlos UFSCar, Brazil;Natl Hellen Res Fdn, Greece.
    Jiusti, Jeanini
    Fed Univ Sao Carlos UFSCar, Brazil.
    Silva, Lais Dantas
    Fed Univ Sao Carlos UFSCar, Brazil.
    Martins Rodrigues, Ana Candida
    Fed Univ Sao Carlos UFSCar, Brazil.
    Long-term stability of laser-induced defects in (fluoride-)phosphate glasses doped with W, Mo, Ta, Nb and Zr ions2018In: Journal of Non-Crystalline Solids, ISSN 0022-3093, E-ISSN 1873-4812, Vol. 498, p. 401-414Article in journal (Refereed)
    Abstract [en]

    Laser-induced defects in glasses are of considerable interest for many applications from optics to photonics. The importance of low-level impurities of polyvalent ions in aiding defect formation has been identified early on. (Fluoride-)phosphate glasses are used today as laser materials, waveguides, amplifiers and luminescing materials, all sensitive to a change of the materials transmission by the interaction with light during application. To better understand the processes of defect generation and recovery, a systematic comparison of defect formation in various glasses and for various radiation sources and dopants has been conducted over the last decades. Here we will focus on (fluoride-) phosphate glasses doped with 50 to 5000 ppm of the 4d and 5d ions Zr, Nb, Ta, Mo and W. Glasses were melted under air or under reducing conditions in order to shift the redox equilibrium of the dopants before irradiation with either the 193 nm or 248 nm excimer laser. Only for W, Mo and Nb reduced ion species were confirmed by optical and/or ESR spectroscopy in the pre-irradiated glasses. However, irradiation showed for all metaphosphates the presence of reduced dopant species (W5+, Mo5+, Ta4+, Nb4+, Zr3+), acting as extrinsic hole centers (HC) after being photo-oxidized by laser irradiation to the fully oxidized d ions (Mn+)(+)-HC. Only for Ta5+ with its (Ta5+)(-)-electron center (EC), photo-reduction to the tetravalent ion was observed. Defect recovery was followed up to 16 years after the irradiation experiments, showing that most (Mn+)(+)-HC were very stable, while intrinsic HC either recombined with EC or converted into extrinsic (Mn+)(+)-HC. Due to ubiquitous iron impurities, even these high purity glasses with iron levels of 5-10 ppm or less, showed the formation of (Fe2+)(+)-HC.

  • 7.
    Wojcik, Natalia A.
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology. Gdansk Univ Technol, Poland.
    Jonson, Bo
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Möncke, Doris
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology. Natl Hellen Res Fdn, Greece.
    Polies, D.
    Natl Hellen Res Fdn, Greece.
    Kamitsos, E. I.
    Natl Hellen Res Fdn, Greec.
    Ghassemali, E.
    Jönköping University.
    Seifeddine, S.
    Jönköping University.
    Eriksson, M.
    Stockholm University.
    Ali, Sharafat
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Influence of synthesis conditions on glass formation, structure and thermal properties in the Na2O-CaO-P2O5 system doped with Si3N4 and Mg2018In: Journal of Non-Crystalline Solids, ISSN 0022-3093, E-ISSN 1873-4812, Vol. 494, p. 66-77Article in journal (Refereed)
    Abstract [en]

    Oxynitride phosphate glasses and glass-ceramics were prepared using new synthesis routes for phosphate glasses. Materials were melted from pre-prepared glass samples in the system Na-Ca-P-0 with addition of Mg and/or Si3N4 powders under different preparation conditions. The melting process was conducted at 1000-1500 degrees C either under air or nitrogen atmosphere to obtain materials with different nitrogen content. Their topography and structure were characterized by Confocal Microscopy, Scanning Electron Microscopy, X-ray powder diffraction and Raman and infrared spectroscopy techniques, while their chemical compositions were examined by Energy Dispersive X-ray spectroscopy (EDS). All materials prepared under nitrogen atmosphere were found to contain a relative low quantity of nitrogen and high amount of Nb leached from the crucible. The reaction with the Nb crucible was not previously observed for silicon-based oxynitride glasses. The synthesized materials form two groups: glasses and glass-ceramics. The first ones, were prepared under air and nitrogen atmospheres at temperatures up to 1400 degrees C, and were found to be amorphous and homogeneous. Raman and infrared spectroscopy measurements confirm the presence of amorphous phosphates in the synthesized materials. The samples of the second group were prepared at temperatures above 1400 degrees C and were found to be translucent and partially crystallized. They contain nanocrystallites of calcium and sodium phosphates including hydroxyapatite (HAp). The thermal properties of samples were studied by Differential Scanning Calorimetry (DSC). The obtained glass transition temperatures range from about 360 degrees C to 640 degrees C and exhibit high values for glass-ceramic materials. Stability is improved in the studied glass-ceramics because of the increased degree of network polymerization of the remaining glassy matrix. The approximate fragility index decreases two times for oxynitride materials compared to the primary glass. The synthesized new materials may be competitive to well-known bioactive phosphate glasses thanks to their improved stability by Mg, Si, N and Nb doping.

  • 8.
    Wójcik, Natalia A.
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology. Gdańsk University of Technology, Poland.
    Ali, Sharafat
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Möncke, Doris
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology. Alfred University, USA;National Hellenic Research Foundation, Greece.
    Kamitsos, Efstratios
    National Hellenic Research Foundation, Greece.
    Segawa, Hiroyo
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology. National Institute for Materials Science, Japan.
    Eriksson, Mirva
    Stockholm University, Sweden.
    Jonson, Bo
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    The influence of Be addition on the structure and thermal properties of alkali-silicate glasses2019In: Journal of Non-Crystalline Solids, ISSN 0022-3093, E-ISSN 1873-4812, Vol. 521, article id 119532Article in journal (Refereed)
    Abstract [en]

    Be-Na-(Li)-Si oxide glasses containing up to 15 mol% of BeO were prepared. Their structure was characterized by X-ray powder diffraction and Raman as well as infrared spectroscopic techniques, while their chemical compositions were examined by Inductively Coupled Plasma Optical Emission Spectrometry. All materials were found to be amorphous and contain Al contaminations from minor dissolution of the alumina crucibles. The results of Raman and IR spectroscopies showed that BeO addition to Na-(Li)-Si glass systems resulted in the formation of [BeO4/2]2− tetrahedra which are inserted into the silicate glass network, demonstrating the intermediate glass-forming role of BeO. In parallel, the effective destruction of Si-O-Si bridges was observed by vibrational spectroscopy. The glass transition temperature was studied by Differential Thermal Analysis and found to range from about 431 °C to 551 °C. A significant increase in Tg by 70 °C was found as SiO2 was substituted by up to 15 mol% BeO.

  • 9. Wójcik, Natalia A.
    et al.
    Jonson, Bo
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Möncke, Doris
    Alfred University, NY, USA.
    Barczyński, Ryszard
    Kupracz, Piotr
    Kamitsos, Efstratios
    Ghassemali, Ehsan
    Seifeddine, Salem
    Eriksson, Mirva
    Ali, Sharafat
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Influence of synthesis conditions on glass formation, structure, thermal and electrical properties in the Na2O-CaO-P2O5 system doped with Si3N4 and Mg2018Conference paper (Refereed)
  • 10.
    Wójcik, Natalia A.
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology. Gdańsk University of Technology, Poland.
    Jonson, Bo
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Möncke, Doris
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology. National Hellenic Research Foundation, Greece;Alfred University, USA.
    Kamitsos, Efstratios
    National Hellenic Research Foundation, Greece.
    Segawa, Hiroyo
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology. National Institute for Materials Science, Japan.
    Karczewski, Jakub
    Gdańsk University of Technology, Poland.
    Ali, Sharafat
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    The effect of nitrogen on the structure and thermal properties of beryllium-containing Na-(Li)-Si-O-N glasses1919In: Journal of Non-Crystalline Solids, ISSN 0022-3093, E-ISSN 1873-4812, Vol. 522, article id 119585Article in journal (Refereed)
    Abstract [en]

    Two oxynitride glass series with the composition of 35Na2O-5BeO-(60-x)SiO2-xSi3N4 and 9Li2O- 27Na2O-5BeO-(59-x)SiO2-xSi3N4, were prepared. The glasses' topography and structure were studied by Scanning Electron Microscopy and Raman spectroscopy. The composition was analyzed by Inductively Coupled Plasma Optical Emission Spectrometer, SEM-EDS and nitrogen and oxygen elemental analyzer. Na-(Li)-Be-silicate glasses were found to contain up to approximately 3.4 (or 5.2 for EDS measurements) at.% of N, respectively. The samples were homogenous in their topography and compositions of their cross-sections.

    The presence of three-fold coordinated nitrogen atoms in Na-Be-Si-O-N glasses results in higher degree of polymerization as was observed by Raman spectroscopy. The spectrum of analogous glasses with lithium did not show a significant decrease in Q2 units but exhibit the presence of Q4 units which also indicates a polymerization of the network. The incorporation of nitrogen in these glasses leads to the increase of the glass transition temperature and thermal stability.

  • 11.
    Zehnder, Christoffer
    et al.
    Rhein Westfal TH Aachen, Germany.
    Peltzer, Jan-Niklas
    Rhein Westfal TH Aachen, Germany.
    Gibson, James S. K. -L.
    Rhein Westfal TH Aachen, Germany.
    Möncke, Doris
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology. Natl Hellen Res Fdn, Greece.
    Korte-Kerzel, Sandra
    Rhein Westfal TH Aachen, Germany.
    Non-Newtonian Flow to the Theoretical Strength of Glasses via Impact Nanoindentation at Room Temperature2017In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, article id 17618Article in journal (Refereed)
    Abstract [en]

    In many daily applications glasses are indispensable and novel applications demanding improved strength and crack resistance are appearing continuously. Up to now, the fundamental mechanical processes in glasses subjected to high strain rates at room temperature are largely unknown and thus guidelines for one of the major failure conditions of glass components are non-existent. Here, we elucidate this important regime for the first time using glasses ranging from a dense metallic glass to open fused silica by impact as well as quasi-static nanoindentation. We show that towards high strain rates, shear deformation becomes the dominant mechanism in all glasses accompanied by Non-Newtonian behaviour evident in a drop of viscosity with increasing rate covering eight orders of magnitude. All glasses converge to the same limit stress determined by the theoretical hardness, thus giving the first experimental and quantitative evidence that Non-Newtonian shear flow occurs at the theoretical strength at room temperature.

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