Unlocking the centuries-old secrets of gold-ruby glass

	Ahmed Issa ’09 spent his summer in Germany conducting research in the Dortmund University laboratory.

According to legend, a nobleman discovered cranberry or gold-ruby glass by tossing a gold coin into the molten glass. When it cooled, the glass appeared crimson.
Although the nobleman is a myth, his story contains a nugget of truth. Gold-ruby glass is formed by adding a miniscule amount of gold into the liquid glass—a technique employed by the Romans in the fourth century and popularized by the wealthy in 19th century England.
Although the creation of such metal-infused glass is ancient, scientists have only recently understood that gold-ruby glass receives its characteristic color from gold nanoparticles—metal pieces so small that they are measured in nanometers or billionths of a meter. One nanometer is about the width of a DNA strand.
Gold-ruby glass still presents many mysteries to scientists, as Ahmed Issa ’09 discovered. The materials science and engineering major first learned of gold-ruby glass from Himanshu Jain, the Diamond Chair and Professor of materials science and engineering and director of the International Materials Institute for New Functionalities in Glass (IMI-NFG).
Issa asked Jain for a research project. Jain suggested that he assist Rajan Anavekar, a professor at Bangalore University in India. Anavekar was examining the properties of gold-ruby glass as a visiting researcher at Lehigh University.
Issa then began a project that would eventually connect glass researchers from five continents. Although none of the researchers studied the same type of glass, their collaborations led to individual discoveries.
“People are thinking everywhere”
Research in glass has changed nearly everything, from architecture to communication. Despite its value, Jain explains that glass research has become more fractured.
Privately funded labs, such as Bell Labs and IBM, have closed, and some universities in the United States and England that were once bulwarks in glass research have focused on other areas of research. Meanwhile, scientists in other countries, particularly in Japan, are expressing more interest in glass.
“People are thinking, and innovation and curiosity are everywhere. Bright ideas come from all corners of the world, near and far. It is important for researchers and scientists to collaborate,” Jain says.
In 2004, the National Science Foundation created six IMIs to encourage learning across national borders. Each IMI has a different specialty and is typically directed by multiple universities. Lehigh University hosts the IMI for New Functionality in Glass and is directed by Jain and Carlo Pantano, Distinguished Professor of Materials Science and Engineering at Pennsylvania State University.
“We have two goals, one is research and the other is education,” Jain says. “We try to educate people at all levels, graduate, undergraduate, high school and the public at large.” Among their educational activities, the IMI-NFG has run outreach programs and maintains a free on-line learning library.
IMI-NFG also has an extraordinarily high ratio of published research compared to its investments. “This ratio is high because the program is a catalyst,” Jain says. Most IMI-NFG researchers receive funding from organizations outside the program, but they rely on the IMI-NFG for connections.
In four years, more than 350 people from 31 countries have participated in IMI-NFG’s research exchange programs, undergraduate study programs, workshops and schools. The IMI-NFG has arranged 74 exchanges between researchers at U.S. and foreign universities, and three or four more research exchanges are scheduled for the spring of 2009.
Anavekar was one of these exchanges. Issa was another.
“Working with the best”
After Anavekar left Lehigh at the end of the 2007 fall semester, Issa and Jain redefined Issa’s project. Instead of studying gold-ruby glass, which is composed of three components, he would focus on a simpler two-component glass that was also tinted red by gold nanoparticles.
Issa spent his spring semester preparing samples to test at Dortmund University in Germany that summer. There, Issa measured his glass’s dielectric properties to determine how easily it transmits electricity.
“Lehigh is a great research institution, but no university has everything,” Issa says. “There are things that they do really well there (in Dortmund), and there are things that we do really well here. You can imagine how great it is to be trained by the best researchers here and the best there.”
Three months later, Issa returned to Lehigh with data and newly acquired technical skills.

	Iolanda Klein

Jain then introduced him to Iolanda Klein, a graduate student in chemistry at São Paulo State University in Brazil. Klein was characterizing the chemical structure and properties of a glass made from tungsten oxide and embedded with silver nanoparticles.
Her laboratory in Brazil had already identified that the tungsten oxide glass, without nanoparticles, might be used as an optical memory device, such as those found in computer hard drives.
“We thought we know this glass is useful for optics and we know glasses in general with metal nanoparticles are also good for optics. Why not join them together to see if it improves?” Klein says.
Before they could determine its optical properties, the Brazilian team wanted to know the chemical structure and physical properties of tungsten oxide glass with silver nanoparticles. They sent Klein to Lehigh University to use the school’s XPS or X-ray Photoelectron Spectroscopy machine. The machine beams x-rays at a material to determine its composition, chemical bonding and electronic state.
“Lehigh has one of the best XPS machines in the U.S., so it’s one of the best in the world,” Klein says.
After Klein finished testing her glass, she and Issa compared results and found similarities between the three glasses with embedded nanoparticles.
“Although people are working on different projects, you start seeing the same line of thought,” Issa says. “It doesn’t matter if it’s this type of glass or that type, if it’s this metal or that metal, you start seeing it as an underlying phenomenon.”
This understanding might not have occurred without the IMI-NFG. Issa, who himself was born in Egypt and moved to New Jersey as a teenager, reflected on their cross-border collaboration.
“Rajan is from India, and I’m from America-slash-Eygpt, so Africa. Iolanda is from South America, and then Lehigh is in North America, and Reiner is from Europe. So I think that covers it, except for Australia,” he says.
--Becky Straw