Hot glass. Ice-cold water. Watch what happens.

This post is part of our “Tough as Glass” series.

At SCHOTT, we love pushing our glass to the limits. Recently, we gave incredibly hot glass an ice bath, just to see if it would crack.

The set-up was simple: An annealing oven, a bucket of ice water, and some sheets of glass-ceramic. Would the glass-ceramic crack when its temperature plummeted by 1,400° F (760° C) in the span of just a few seconds?

Our first test case: Soda-lime glass

First, we tested a piece of ordinary soda-lime glass, the type of glass in your bedroom windows or that makes up the beer bottles in your fridge. After heating it to nearly 600° F (315° C) in an annealing oven, we dipped the soda-lime glass in a bucket of ice water that registered at just 50° F (10° C).

That ordinary glass couldn’t take that rapid drop in temperature, causing it to crack in hundreds of places. So what did we do next? We turned up the heat and tried the same test on glass-ceramics.

Next up in the oven: glass-ceramics

The next test subjects were three pieces of SCHOTT’s NEXTREMA glass-ceramic. Cranking up the heat to nearly 1,500° F (815° C), we roasted three pieces of NEXTREMA in the oven. These sheets of glass-ceramic look different – we used transparent, translucent, and opaque versions — but all were identical in chemical structure and properties.

When the temperature was right, we removed each piece from the oven and immediately dipped it in the frigid water, again at 50° F (10° C). That means the glass went from a scorching 1,470° F (800°C) oven to the icy bath — a difference of more than 1,400° F (760° C). It was sure to crack, right?

A specialty glass that boasts a high thermal shock resistance and low coefficient of thermal expansion, none of the sheets of NEXTREMA glass-ceramic cracked or were damaged after their surface temperatures plummeted. Its properties mean this glass-ceramic would survive even the most extreme temperature fluctuations.

Glass-ceramic’s super power: thermal shock resistance

The chemical makeup of NEXTREMA glass-ceramic results in a material that can withstand extreme and rapid temperature fluctuations, which means it won’t shatter when it’s exposed to the elements (like high heat or frigid cold). That’s why we use NEXTREMA in grill lids and in other industrial applications known for sudden temperature changes: Its thermal shock resistance allows it to be heated and cooled extremely quickly while remaining structurally sound.

Remember, while NEXTREMA comes in different shapes and varieties (from transparent to opaque, as thin as 2 millimeters, and either curved or flat), its thermal properties allow it to withstand extreme temperatures and rapid fluctuations in temperature and still not shatter.

In residential uses like grills and toasters, and even in industrial furnaces, we test glass-ceramics often to ensure they withstand extreme heat changes without fracturing. Our tests show that NEXTREMA holds up to even the most extreme scenarios. So have no fear turning your grill burners to high – that glass grill lid won’t shatter if a sudden thunderstorm interrupts your summer barbecue.

What should we test next? Let us know with a comment below.