Method of manufacturing a container (14) from a blank (2) of thermoplastic material having a body (4) extending along a principal axis (A), which comprises: A selective heating step in which the body (4) of the blank (2) is exposed to monochromatic or pseudo-monochromatic infrared radiation, the power of which is modulated along the principal axis (A) of the body (4) in such a way that said body has alternating hot annular regions (4A, 4C, 4E, 4G, 4I), the temperature of which is far higher than the glass transition temperature (Tg) of the material, and comparatively colder annular regions (4B, 4D, 4F, 4H), the temperature of which is close to the glass transition temperature (Tg); A forming step in which a fluid under pressure is injected into the blank (2) thus heated, said step being carried out in free expansion.