How can i make rubber stay streched

well i need this rubber to remain streched,
ive tried heating it,freezing it and just leaving it streched for a day,but it doesn't want to stay streched. any ideas?

You stress the rubber until it reaches the elastic limit and then it is strained so it will not return to it's original shape.
By the way you could never reach absolute zero with liquid nitrogen.

I think freezing - but close to absolute zero - ie put it in liquid nitrogen.

keep applying the force until the polymers rearrange themselves in that shape or something like that.

Keep it tied or pinned at both ends!

yes the first one is the correct answer