The cause of the disaster was the failure of the primary and secondary O-ring seals in a joint in the right Space Shuttle Solid Rocket Booster (SRB). The record-low temperatures on the morning of the launch had stiffened the rubber O-rings, reducing their ability to seal the joints. Shortly after liftoff, the seals were breached, and hot pressurized gas from within the SRB leaked through the joint and burned through the aft attachment strut connecting it to the external propellant tank (ET), then into the tank itself.
Wikipedia
We do not know exactly how cold the Viton O-rings had become, but they were ‘very cold’. Viton is designed for high temperatures, NOT for use in the cold. Say -20 C to+205 C long term, +250 C short duration.
Personally, I think relying on two huge-diameter O-rings to seal against the temperature range and pressure expected in the booster was ethically unwise, maybe even criminally so.
I recollect from the time that the chief engineer tried to stop the launch for this reason, but the relevant mgr told him to take off his engineering hat and put on his management hat. ‘We have to launch today.’
You see what happens when pollies and bureaucrats ignore STEM staff? Death.
My 2c
Cheers