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GOMD 2012 Award Winners

 

2012 Glass & Optical Materials Division Spring Meeting

Final Program

 

George W. Morey Award Lecture

Edgar D. Zanotto, Professor, Vitreous Materials Lab, Federal University of São Carlos, Brazil

 

Thirty-five Years of Glass Research – A tribute to my co-authors

Zanotto will reexamine a relevant part of the research work on glass crystallization that he has carried out in the past three decades under the guidance of six distinguished co-authors – all G.W. Morey awardees – namely Don Uhlmann, Mike Weinberg†, Larry Hench, Adrian Wright, Prabhat Gupta and Dick Brow. Most of the past research focused on unveiling the intricate aspects of crystal nucleation, growth and overall crystallization of glass, underpinned by an understanding of their relationships with structure and ion dynamics (molecular diffusion, viscous flow and relaxation). He will focus on a number of experimental and calculational studies of a fundamental nature about the applicability of the nucleation theory to glasses, about glass forming ability (on cooling) versus glass stability against crystallization (on heating), about the possible relationship between the molecular structure and nucleation mechanism of glass, and glass relaxation at room temperature (do cathedral glasses flow?). He will also discuss recent work of a more technological nature on the control of phosphate glass crystallization and on highly bioactive glass-ceramics. Finally, Ed Zanotto will summarize recent work with Vlad Fokin and other co-authors on several diffusion processes in undercooled liquids.

 

Biography: Zanotto holds a degree in Materials Engineering from the Federal University of São Carlos, Brazil, an MSc in Physics from the University of São Paulo, Brazil, and a PhD in Glass Technology from Sheffield University, UK (1982). He is a Professor of Materials Science and Engineering and head of the Vitreous Materials Laboratory – UFSCar. Zanotto has coordinated about 20 research projects funded by government agencies and an equal number by industry. EDZ has published about 150 original and review papers in peer reviewed journals, plus about 50 papers in conference proceedings, 15 book chapters, 2 books, and has advised about 55 MSc, PhD and post-doctoral research projects, plus about 80 scientific initiation projects. He is an editor of the Journal of Non-Crystalline Solids and member of the international advisory boards of four other glass-related periodicals. He is a member of the international Academy of Ceramics, the Academy of Sciences of the Developing World (TWAS), the Brazilian Academy of Sciences, a fellow of the SGT (UK), and of the São Paulo State Academy of Sciences.

 

2012 Norbert J. Kreidl Award

Mathieu Bauchy, PhD Student, Université Pierre et Marie Curie

 

Topological Constraints and Rigidity of Network Glasses from Molecular Dynamics Simulations

Topological constraint theory provides an interesting means to understand the important microscopic physics governing the thermal, mechanical and rheological properties of glasses with changing compositions, while filtering out unnecessary details that ultimately do not affect its macroscopic properties. It has been successful in predicting compositional trends in covalent network-forming glasses such as chalcogenides. Its application appears however more challenging in iono-covalent glasses such as silicates where neighbors/bonds and angles need to be properly defined. Here we derive such constraints for different alkali silicates using an atomic scale approach (Molecular Dynamics, MD) combined with partial bond angle distributions (PBAD). The latter allows having access to the second moments (standard deviations) of the distributions. Large (small) standard deviations correspond to large (small) angular excursions around a mean value, and are identified as broken (intact) bond-bending constraints. A similar procedure is used for bond-stretching constraints. Systems examined include glassy and liquid disilicate 2SiO2-M2O (LS2, NS2, KS2). In the glass, MD constraint counting closely matches Maxwell enumeration of constraints using the octet binding (8-N) rule. Results show that the standard deviations of the partial bond angle distributions increase with temperature and suggest a softening of bond-bending constraints. A bimodal bonding oxygen distribution is obtained for T>Tg, and the fraction of thermally activated broken bond-bending constraints computed as a function of temperature. As a preliminary work, pressure effects are also presented. Overall, these results provide a microscopic rationale for extending constraint counting from chalcogenides to complex oxides, and also a numerical basis for recent functional forms of temperature-dependent constraints proposed from energy landscape approaches.

 

2012 Stookey Lecture of Discovery
John B. MacChesney

John B. MacChesney, Bell Laboratories Fellow (Retired)

 

Optical Fiber Research at Bell Laboratories
The advantage of optical communications has long been recognized and work to improve the transmission of light in glass has been pursued. A project was started at Bell Laboratories in the early sixties seeking a soda-lime-silica glass. It progressed using purified constituents but never achieved satisfactory loss. Vapor-deposition of high silica germania-doped glass started in the early 1970’s. Here, silicon and germanium chloride with oxygen flowed through a silica tube heated from the outside known as Modifed Chemical Vapor Deposition (MCVD). Doped silica colloidal particles deposit on the tube’s wall by thermophoresis and sinter to glass as a heat source moved along the length of the tube. Subsequent collapse of the tube yields to a fiber preform with the deposited material as the higher index core when drawn to fiber. The small glass cylinders require over-cladding by larger silica cylinders. To improve the economics, a sol-gel project sought such large silica cylinders. Here, by manipulation of surface charge on commercial colloidal silica dispersed in water, large gel bodies could be warmed and sintered to waveguide quality glass to serve this need. During this same period, a more important and more challenging project was undertaken to produce amplifier fiber . Amplification occurs when inner-shell electrons of rare earth ions are pumped to higher levels and triggered to fall to ground state by a specific signal wavelength. The challenge is to incorporate large rare earth ions into silica at high temperatures. By themselves, they form a separate phase. Successful transport and deposition was accomplished by developing a complex rare earth- aluminum chloride vapor which resulted in deposition of suitable composition in the MCVD apparatus. Such fibers spliced into ordinary fibers allow transmission of dozens of optical signals in a single fiber. This forms the backbone of modern telecommunication systems.

 

Biography: Upon receiving a PhD, MacChesney joined Bell Laboratories where he engaged in research on ceramics and single crystals of interest for their electrical or magnetic properties. In 1972, his attention turned to glass, specifically to produce vitreous silica of purity and configuration needed for optical fibers. This resulted in the invention of the Modified Chemical Vapor Deposition Process (MCVD) used worldwide to produce a significant fraction of the presently installed fiber. Later, his work concentrated on means to deliver erbium or other rare-earth ions to the processes for making amplifier fibers. From that time on, he has worked on specialty fibers including chemical sensors. Concurrently, together with D.W. Johnson, Jr., they demonstrated a sol-gel process for making large silica bodies, which was developed for commercial fiber production and later for micro-structured fibers. He is, generally, regarded as a materials scientist and innovator, credited with over one hundred domestic and foreign patents and a similar number of publications. Among these are: key patents for the processing of photonic components. His work has received national and international recognition which includes: The Commonwealth Award of America/Institute of Electrical Engineers, and The Charles Draper Award by the National Academy of Engineering (U.S.A.): of which he is a member. He is also a member of the National Academy of Ceramics, which has named him and Johnson as recipients of the 2000 Ceramics Award. In 1993, he was awarded the New Jersey Scientist of the Year. He is a Fellow of Bell Laboratories and The American Ceramic Society. He was awarded a B.A. by Bowdoin College, Brunswick, Maine and a PhD by The Pennsylvania State University. He has served as adjunct professor at Brown University and Rutgers University, as well as the Kwangju Institute of Science and Technology (Korea), and he also serves as a liaison between the materials Engineering Section of NAE and the National Research Council. Until recently, he was employed by OFS Fitel Laboratories, the successor to the fiber optics section of Lucent’s Bell Laboratory. With the continuing down-turn of OFS revenue, he stepped aside to become a consultant, the purpose being to pursue initiatives and funding through collaboration with Academia.

 

 

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