Solidlike and liquidlike linear viscoelastic responses were observed at low and high temperatures (T) for polystyrene-polyisoprene-polystyrene (SIS) triblock copolymers dissolved in an I-selective solvent, n-tetradecane (C14). These SIS systems behaved as thermoreversible physical gels, with the microphase-separated S domains working as the cross-links at low T. Linear responses of those systems were examined in the vicinity of the sol-gel transition temperature T-gel. For the systems fully equilibrated in an isothermal state at T-gel, the power-law behavior, G＇(omega) similar to G "(omega) similar to omega(n), was observed only at high frequencies to, and a separate slow relaxation mode was observed at low omega. For the system quenched from high T(>T-gel) to low T(

Keywords:STYRENE TRIBLOCK COPOLYMER;SOL-GEL TRANSITION;ANGLE X-RAY;LINEAR VISCOELASTICITY;DIELECTRIC BEHAVIOR;POINT;TETRADECANE;SCATTERING;ELASTOMER;RHEOLOGY