B. A. Sava, A. Diaconu, L. D. Ursu, M. Elisa, I. Stamatin, F. Nastase, C. Nastase, Structure of ecological lead free silicate glasses, Opoelectron. Adv. Mater. – Rap. Comm., 3/5 (2009) 435 – 438

Title: Structure of ecological lead free silicate glasses

Abstract: The paper investigates ecological glasses prepared from non-toxic raw materials. These glasses have compositions belonging to the quaternary oxide systems: SiO(2)-R'(2)O-R '' O-R"'O(2), where R' is Na or K, R '' is Ca or Mg and R"' is Zr or Ti. The present work aims to replace barium and lead oxides by potassium, magnesium, zirconium and titanium oxides, in order to use such materials as lead free crystals and for other applications. Some of the characteristic temperatures, such as: vitreous transition point, low and high annealing points, softening point and also the thermal expansion coefficient between 20 and 320 degrees C are measured. FTIR and Raman spectroscopy provide interesting structural information. The characteristic vibration modes for silicon and titanium oxide are discussed. The vitreous network forming role of zirconium oxide is put in evidence. The refraction index calculation and UV-VIS transmission diagrams are presented and discussed.

Key words: Ecological glass; Lead free glass; FTIR; Raman; UV-VIS