Hello, I am working on a science fair project with my son. His project is about the mobility of polymer chains depending on temperature and pressure. As part of his project we want to flash freeze a piece of plastic to show how brittle it becomes. We bought instamorph, which is polycaprolactone. It has a glass transition temperature of -60 celcius. Next, I bought some dry ice, put it in a plastic bottle and poured 99 percent isopropyl alcohol into it to create a cooling bath. This cooling bath should be about -77 celcius right? Lower than the glass transition temperature. So then I dipped the piece of plastic into the bath, held it there for about 30 seconds and pulled it out. I tried to smash it to test the brittleness but it didnt break. It felt the same, but just cold. Why is that? And how can I make it brittle?