What will happen to the electric field of capacitor if temp of polarized dielectric is increased?
That will depend on the dielectric. There will be two main
effects - any change in the permeativity of the dielectric, and
thermal expansion which will increase the distance between the
plates. There will also be an change (probably an increase), in
leakage current through the dielectric. Any change is very likely
to be small or insignificant - I have worked in a factory making
capacitors and temperatures were very variable, not controlled, for
measurements of capacitance.