Abstract: Polymers which comprise polymer chains of terpolymer type which are constituted by poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) of PEO-PPO-PEO form, which are modified at their termini by groups which can essentially be other chains of PEO-PPO-PEO, acid segments, amine groups or PEOs, these chains being linked to the terpolymer chains via chemical bridges which are constituted by urethane bridges, urea bridges, allophanate bridges and biuret bridges, and which comprise more than 80% by weight of said PEO-PPO-PEO. Thermoreversible physical gels of high viscosification index, which contain these polymers, and their uses. Preparation of these polymers and of these gels.