Reminiscent of a William Morris print, this micrograph shows eutectic crystallization on the surface of a CaO-Li2O-SiO2 glass. The lithium siicate crystals do not impinge on one another because of the limiting effects of lithium depletion in the diffusion layer surrounding the crystals. The scale bar represents 100 microns. Optical microscopy, reflected light. Credit: Fokin, 2011; Wiley.
For the record—beauty is abundant in the physical sciences. If you need proof, look no further than the book Crystals in Glass: A Hidden Beauty, by Edgar Zanotto. Zanotto is an ACerS member (Glass and Optical Materials Division) and professor of materials science and engineering at the Federal University of São Carlos in Brazil. In this book, Zanotto celebrates his 35 years studying crystallization in glass by sharing with us his favorite micrographs of crystals in glass.
Zanotto began studying glass crystallization in graduate school and has been a leader in the field ever since. In the course of his career thus far he has written more than 250 papers and generated thousands of micrographs. In an email he says, “My original idea was to select some dozen micrographs that show some important phenomena representing glass crystallization mechanisms, including internal, surface, homogeneous, heterogeneous, and eutectic, crystal nucleation and growth.”
The book’s Introduction provides a cursory review of the evolution of nucleation and crystallization in glass theory, starting with Zanotto’s doctoral work on amorphous phase separation. He also touches on classical nucleation theory, metastable phase separation, the General Theory of Transformation Kinetics, homogeneous nucleation, the relationship between molecular structure and nucleation mechanisms, and surface nucleation and crystal growth.
The 50 images that he ultimately selected for the book relate to different glass crystallization phenomena including internal nucleation in glass, surface nucleation on glass, viscous sintering with concurrent crystallization, eutectic crystallization, and cracks and bubbles in glass-ceramics.
The micrographs, many of which are color plates, are beautiful. In some respects, the micrographs themselves document advances in optical microscopy, too. Compare, for example, the images shown from Zanotto’s doctoral research (see featured image above) in the mid-1970s to recent images from 2011 (above).
Zanotto is a joyful person, and his delight comes through every page of this book. His review of the evolution of glass crystallization theory highlights the work of his many students and collaborators from around the world. The reader cannot help but be swept up by his enthusiasm for the subject.
The technical content of the book—mostly in the Introduction—provides a satisfying level of rigor to be interesting to materials scientists. However, Zanotto writes with a light enough touch that the nonscientist is unlikely to close the book in frustration. A more likely reaction for nontechnical readers might be the satisfying dawn of understanding: “So, that’s what a glass-ceramic is!”
The book is small—only 136 pages—and would make a lovely addition to the library of a colleague, graduating student, or photography enthusiast. It is available in hardcover ($59.95) or as an e-book ($47.99) through the Wiley website. ACerS members may purchase the hardcover for the discounted price of $38.96 by entering the promotion code “CERAM” at checkout.
Luckily, Zanotto has firm plans to continue to lead the global investigation of crystallization processes in glass. Earlier this year he received funding for 11 more years of glass research.
Crystals in Glass: A Hidden Beauty
Table of contents
Introduction: 36 Years of Research and Discoveries about Glass Crystallization
Glass Myth Shattered (Science Now, May 16, 1998)
Letter from S. D. Stookey – The Inventor of Glass-ceramics
Crystals in Glass – A Celebration of Science and Art
Internal Nucleation in Glasses
Surface Nucleation on Glasses
Viscous Sintering with Concurrent Crystallization
Cracks and Bubbles in Glass-ceramics
Reviews of Crystals in Glass: A Hidden Beauty
About the Author