Alyssa Dumire, Director of Education
Glass has a reputation for being fragile, and it certainly can be. Perhaps you use plastic cups for everyday drinking and reserve the fancy glassware for more special occasions. But, peruse those kitchen cabinets further and you may find a piece of today’s art term: borosilicate glass (sometimes known as pyrex). While lead glass was developed for decorative applications way back in the seventeenth century, the origins of borosilicate glass are scientific and much more recent. In addition to various utilitarian applications, its thermal resistance makes it the glass of choice for many flameworkers creating delicately detailed sculptures.
The second half of the 1800s was a time of great scientific discovery, and scientists across disciplines relied on glass for their instruments (and still do!). In 1876, Ernst Abbe, a professor of physics and director of a telescope observatory in Jena, Germany, wrote a report on the abysmal state of scientific glass. Only two main types of glass were available, soda-lime or lead, both of which lacked the clarity and purity needed for Abbe’s telescope lenses. Material research in glass had stagnated, stalling progress in other fields, Abbe argued. Why not treat glass formulas like a baker does recipes, adjusting ingredients according to the desired outcome? Meanwhile in Witten, Otto Schott returned to work in his family’s glass factory after earning a doctorate in chemistry (with a specialization in glass). Upon reading Abbe’s report, he began sending the professor samples of his experimental glasses for testing in the lab. Schott was adding various other elements to glass, working his way across the periodic table. His breakthrough came after two years with the addition of boron–the “boro” in borosilicate. He moved to Jena to work more closely with Abbe and microscope maker Carl Zeiss, founding his own glass company Schott & Associates, whose first product was commonly known as “Jena glass.”
Schott found that small amounts of boron improved the optical qualities of window glass. Slightly more made glass that didn’t react to acids or other chemicals, making it an excellent choice for beakers and test tubes. Still more boron resulted in a material with an extremely low coefficient of expansion when exposed to changes in temperature that would cause other kinds of glass to shatter. The sodium in standard soda-lime expands significantly, but replacing some with boron meant that this new borosilicate glass expanded only one-third as much. It also has a higher melting point, roughly 3000 degrees compared to 2000 for soda lime. This initially required new furnace technology, but now is not any more expensive than standard glass blowing.
Stateside, the history of borosilicate glass, like that of lead glass, centers around Corning Glass Works in New York. To compete with Schott, Corning began employing chemists in 1908. They soon cracked the code on their own formula for borosilicate glass, Nonex (non-expanding), but the German company had already cornered the market on lab glass. The booming railroad industry in the U.S. presented a new problem to be solved: glass signal lights, which warned oncoming trains of impending danger, were especially susceptible to the very conditions that necessitated their use. As rain or snow cooled the outside of the glass, the light heated the inside, causing the glass to crack and shatter. Corning’s Nonex lamps remedied this and boosted the company’s sales, but their sturdiness meant they seldom needed to be replaced, so the hunt was on for another new use for borosilicate glass.
Dr. Jesse Littleton, the first physicist to join Corning’s payroll, was on the case when his wife, Bessie, broke yet another ceramic casserole dish in the oven. Wondering how Nonex would work, Jesse sawed off the top of a battery jar in which Bessie reportedly baked a perfect sponge cake. (And yes, this is that Littleton family: Jesse and Bessie welcomed their son, Harvey, father of the Studio Glass Movement, in 1922!) Corning officially introduced a line of Pyrex bakeware in 1915, and the name became synonymous with borosilicate glass in the U.S. (although nowadays, not all “Pyrex” is made from boro). The invention of Pyrex shifted consumers’ relationship with glass: what was thought of as fragile and delicate could actually be quite durable, and came to be used for all kinds of household and industrial applications.
In the late 1960s, Czech artist Věra Lišková was among the first to experiment with borosilicate glass for sculpture. In the Glass Wing, Lion, above, shows how it can be manipulated in isolated areas: note the long strands of the lion’s mane, achieved by heating small areas with a torch and stretching them out while molten. The thinner the glass, the more quickly it cools, and soda-lime would likely have cracked under such stress. Lišková’s decision to use clear glass, along with its delicately thin surface, calls to mind boro’s scientific applications, an appealing idea for artists interested in the intersection of these seemingly disparate fields.
While “soft” soda lime is by far the most common type of glass, and is even preferred by some flameworkers, the museum’s first Studio Glass acquisition was made from “hard” borosilicate. Ginny Ruffner was the first American woman to work with the material, introducing it to students at the Pilchuck School of Glass as the first flameworking instructor there. Urnscape, above, owes its strength and stability to hard glass.
Borosilicate glass enabled flameworked sculptures to grow in size and complexity thanks both to its thermal shock-resistance and the fact that it is more viscous (less runny) than soft soda lime glass at high temperatures. Anna Skibska capitalized on both properties to develop her namesake technique, stretching canes of borosilicate glass and fusing them into delicate networks that define and fill three-dimensional forms, above.
Visit the FWMoA’s Contemporary Studio Glass wing to see these glass sculptures, and more, currently on view!