A. V. DOBRYNIN* and L. LEIBLER^**

* Department of Chemistry, CB#3290 Venable Hall
University of North Carolina -Chapel Hill, NC 27599~3290, USA

**Unité Mixte de Recherches 167 CNRS-ELF Atochem
B.P. 108, 95 rue Danton, 92303 Levallois-Perret, France

PACS. 64.60-i -General studies of phase transitions.

PACS. 36.20-r -Macromolecules and polymer molecules.

Abstract. -We study the behavior of random A-B copolymers near the Lifshitz point. ln the one-loop approximation the phase transition between homogeneous and ordered phases is a fluctuation-induced first-order phase transition. The period L of the domain structure appearing below the phase transition has unusual temperature dependence L "" 171-1/4 or L "" 171-1/6, where 7 is the reduced temperature distance from the Lifshitz point. The exponent (-1/4 or -1/6) depends on the microscopic parameters of the system.