Glass and Optical Materials: Structure and Properties Characterization in Glass
Sponsored by: MS&T Organization
Program Organizers: Pierre Lucas, University of Arizona

Thursday 8:00 AM
October 20, 2011
Room: C110
Location: Greater Columbus Convention Center

Session Chair: Steve W. Martin, Iowa State University

8:00 AM
Diffusion of Sodium in Sodium Boroaluminosilicate Glasses: Xinwei Wu¹; Jeremy Moskowitz¹; Ruediger Dieckmann¹; ¹Cornell University
     Sodium tracer diffusion coefficients were measured using the radioactive isotope sodium-22 in two series of sodium boroaluminosilicate glasses:[(Na₂O)_0.71(Fe₂O₃)_0.05(B₂O₃)_0.24]_0.2[(SiO₂)_x(Al₂O₃)_1-x]_0.8 and [(Na₂O)_0.73(B₂O₃)_0.24(As₂O₃)_0.03]_0.18[(SiO₂)_x(Al₂O₃)_1-x]_0.82 with the composition parameter x varying between 0 and 1. To study the temperature dependence of the tracer diffusion coefficient and the water influence on it, sodium tracer diffusion experiments were performed by diffusion annealing in dry and wet air at atmospheric pressure at different temperatures from about 200 to about 350 °C. The experimental results obtained will be presented and discussed.

8:20 AM  Cancelled
Formation of Ga-As Nanocrystals in Glasses: Kody Bornstein¹; John Rich¹; S. Sundaram¹; ¹Alfred University
    Commercial borosilicate and soda-lime silicate glasses were used to study Ga-As nanocrystal formation. The nanocrystals were formed by heat treatment in a hydrogen-deutrium atmosphere. The heat-treatment temperature, duration, and H2-D2 ratio were varied in optimizing the nucleation and growth processes. X-ray diffraction, differential thermal analysis, low frequency Raman scattering, UV-Vis-NIR, and FTIR spectroscopies were used to study the processes. Hydroxyl formation in these glasses will be correlated to the formation of nanocrystals. These processes can be described using well-established models.

8:40 AM
Structure of Liquid and Glassy CaSiO3: A Levitation and Neutron Diffraction with Isotopic Substitution Study: Lawrie Skinner¹; ¹SUNY, stony brook / Argonne
    The local and intermediate range atomic structure of high temperature silicate melts has been of long standing interest in geophysics and glass science, due to the effect on viscosity and thermodynamic properties. Calcium silicate glasses in particular have often been used as a benchmark system for testing theories of modifier ordering. They are also studied for their significance in understanding the formation of the earth’s mantle and their role as a major component of soda-lime glass. However, the accurate determination of liquid structure of silicate liquids is problematic due to the high temperatures required. Here we present the first isotopic substitution measurements on an aerodynamically levitated liquid. This allowed direct measurement of the short and intermediate range calcium correlations in molten CaSiO3. These detailed measurements compared to existing data of the glass provide new insight into the structural change between the liquid and glassy states.

9:00 AM  Cancelled
High-Temperature Raman Spectroscopic Investigations of the Two-Alkali Borate Melts: Armenak Osipov¹; Leyla Osipova¹; ¹Institute of Mineralogy IB RAS
     The structure of the Li2O-Na2O-B2O3 melts with total alkali oxides content of 30-67 mol% has been investigated by high-temperature Raman spectroscopy. The Raman spectra are monotonously changed with gradual substitution of one modifier oxide with another if the Li2O+Na2O < 50 mol%. This result indicates that there is a statistical mixing of the cations in the melt structure of such compositions. The study of the mixed alkali borate melts has revealed a nonmonotonic change in the spectra, depending on the ratio of the modifying oxide concentrations if Li2O+Na2O = 67 mol%. Analysis of the spectra points to the significant increase in the fraction of BO33- orthoborate units in the mixed alkali borate melts in comparison with binary Li2O-B2O3 and Na2O-B2O3 melts. It is a manifestation of the nonstatistical of the alkali cation distribution.The study was financially supported by the RFBR (grant No 11-03-00179-a) and SFP program No P-735.

9:20 AM  Student
X-Ray Diffraction and IR Investigation of the Structure of Pressurized Silica Glass: Chia-Ying Li¹; Jonathan Price²; Minoru Tomozawa¹; E. Bruce Watson¹; ¹Rensselaer Polytechnic Institute; ²Midwestern State University
    The effects of high pressure/high temperature treatment on the structure of silica glass were investigated using X-ray diffraction (XRD) and IR spectroscopy. Most of the pressurized silica glasses were partially crystallized, and the percent crystallinity was determined by X-ray diffraction method. Increasing hydrostatic pressure produced higher crystallinity in glass. The pressure relaxation process from higher hydrostatic pressure at constant temperature exhibited shorter relaxation time, which indicates that pressure has the effect of lowering the glass viscosity. The hydroxyl content observed in some of the low pressurized silica glass also produced higher crystallinity and shorter relaxation time due to lower viscosity. The average values of the silica structural parameters, central force constant, non-central force constant, and Si-O-Si bond angle, from the IR peak positions of the three fundamental structural bands: asymmetric stretching, bending, and rocking vibrations were also determined.