Synthesis, structural characterization, and thermal properties of Caa?? and Laa??doped sodaa??lime glasses by laser melting

摘要： Laser melting techniques have been used in the preparation of unconventional glass compositions with high melting temperatures. Thus, we wanted to test the feasibility of using a CO2 laser in the preparation of nitrogen rich oxynitride glasses and nitride silicate glasses. Melting from oxides and metallic raw materials, we wanted to study first glass formation and possible evaporation losses of the glass components. Two glass series were prepared and studied for their structure and thermal properties, one with Ca2+- and a higher melting La3+-doped soda lime silicate series. In less than three minutes of laser melting, spheres of up to six mm diameter were successfully fabricated. The obtained glass samples were homogeneous and transparent in the visible region. X-ray diffraction and Raman spectroscopic analysis confirmed the amorphous nature of the synthesized samples. Sodium losses increase as calcium is added to the soda lime silicate glass. As expected, increasing Ca2+ or La3+ addition leady to increased depolymerization of the silicate network. Moreover, the increases in Tg with the addition of Ca2+ or La3+ ions indicating strengthening of the soda lime silicate glass by increasing strength of the M-O bonds of divalent and trivalent ions over monovalent sodium ions, weak Na-O bonds also resulting in significant evaporation loss during the short laser melting times. The thermal stability decreases upon addition of Ca2+ or La3+ ions to the soda lime silicate glasses.