A process for the preparation of a polymer solution comprises the steps of: mixing a polymer with a solvent to swell the polymer in the solvent; cooling the swelled mixture to a temperature of -100 to -10°C; and then warming the cooled mixture to a temperature of 0 to 120°C to dissolve the polymer in the solvent. According to the present invention, the swelled mixture is cooled at a rate of faster than 1°C per minute, or the cooled mixture is warmed at a rate of faster than 1°C per minute. Apparatuses for the preparation of a polymer solution are also disclosed.