> Beginning in the 1980s, production of clear Pyrex glass products manufactured by Corning (and later Instant Brands, after the consumer division was spun off and renamed) was also shifted to tempered soda–lime glass, like their popular opal bakeware.[27] This change was justified by stating that soda–lime glass has higher mechanical strength than borosilicate—making it more resistant to physical damage when dropped, which is believed to be the most common cause of breakage in glass bakeware. The glass is also cheaper to produce and more environmentally friendly. However, its thermal shock resistance is lower than borosilicate's, leading to potential breakage from heat stress if used contrary to recommendations. ...
> The differences between Pyrex-branded glass products has also led to controversy regarding safety issues—in 2008, the U.S. Consumer Product Safety Commission reported it had received 66 complaints by users reporting that their Pyrex glassware had shattered over the prior ten years yet concluded that Pyrex glass bakeware does not present a safety concern. The consumer affairs magazine Consumer Reports investigated the issue and released test results, in January 2011, confirming that borosilicate glass bakeware was less susceptible to thermal shock breakage than tempered soda lime bakeware.[30] However, they admitted their testing conditions were "contrary to instructions" provided by the manufacturer.[26][31] STATS analyzed the data available and found that the most common way that users were injured by glassware was via mechanical breakage, being hit or dropped, and that "the change to soda lime represents a greater net safety benefit."[28]
The above is why Pyrex cookware is likely to crack and split in microwave cooking,
because of the temperature differential between the microwave rotating platen and the cookware.
Hence the need for a silicone mat thermal insulator to prevent loss.
1) Pyrex cookware is NOT "likely to crack and split in microwave cooking".
These incidents are RARE.
2) The Pyrex name (in the US) includes both soda lime and borosilicate glass. Warning about "Pyrex" is wrong - you should be warning either about soda lime glass, which include many brands besides Pyrex.
3) Thermal shock is much more likely to occur when moving glass from the freezer to the oven, or from the oven to a metal surface, NOT when cooking in the microwave.
I went ahead and skimmed the video. Every example was of putting a hot pan into a cold liquid, with warnings about moving a hot pan to a cold metal surface, or using it to cook on a stovetop.
There were no examples of shattering due to the microwave turntable, nor warnings thereof.
4) My microwave uses a glass turntable. Why doesn't it shatter? Where does the thermal shock come from between the glass container and the glass turntable?
If the thermal shock is between those two, then surely your more worried the glass would shatter if you take it out of the microwave oven and put it on a metal countertop, yes?
(I bet my glass turntable is made of soda lime glass.)
5) Glass shatters for other reasons, like dropping it. As I quoted, "the change to soda lime represents a greater net safety benefit", because soda glass is safer than borosilicate when that happens.
Don't forget that borosilicate glass also cracks with thermal shock.
See also the Wikipedia references, https://www.snopes.com/fact-check/exploding-pyrex/ and https://gizmodo.com/the-pyrex-glass-controversy-that-just-wo... .
