TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The lactone is optionally substituted and optionally saturated 4-11C beta , gamma -, delta and epsilon -lactones such as epsilon -caprolactone (preferred), delta -valerolactone, optionally racemic beta -butyrolactone, optionally racemic delta -caprolactone or gamma -butyrolactone. The lactam is caprolactam, enantholactam, lauryllactam, pyrrolidinone or piperidone. The carbonate is a cyclic carbonate of formula (I). The molar ratio of substituted phosphorus compound to polymeric initiator is 1-3. The substituted phosphorus compound is of formulae (R0-Z-P(=Y1)(X)-Z-R0) (1a), (1b)-(1f), preferably diphenylphosphate, (R)-3,3'-bis(3,5-bis(trifluoromethyl))phenyl-1,1'-binaphthyl-2,2'-diyl hydrogenophosphate or N-((trifluoromethyl) sulfonyl)-diphenylester of phosphoramidic acid. In formula (I),R = 2-20C alkyl or 2-20C alkylaryl (both optionally substituted with one or more substituents of oxo and halo groups such as F, Cl, Br or I).In formula (1a)-(6a),R0 = alkyl;X = OH, SH, (SeH) or NHR1a;R1a = aryl, SO2aryl or SO2CF3;Y1 = O, S or (Se);Z = O or NR2a;R2a = p-tolylsulfonyl, (4-(trifluoromethyl)phenyl)sulfonyl or 2-naphthylsulfonyl; andR = H, phenyl(Ph), 3,5-(phenyl)2C6H3, 2,4,6-(CH3)3-C6H2, 3,4,5-(CH3)3-C6H2, 3,5-(CF3)2-C6H2, 4-tertbutyl-C6H4, CH3O-C6H4, NO2-C6H4, SiPh3, Si(tertbutyl)(Ph)2, 4-biphenyl, 1-naphthyl, 2-naphthyl, 9-anthryl or 9-phenanthryl.    TECHNOLOGY FOCUS - POLYMERS - Preferred Process: The process is carried out: in the presence of initiator; and at a temperature of 0-230 degrees C. Preferred Components: The cyclic monomer is racemic, enantiomerically pure or meso lactides. The cyclic monomer is glycolide. The initiator is a small molecule such as water, pentanol or polymer comprising at least one hydroxyl function. The polymeric initiator is: mono- or polyhydroxylated oligomer or polymer comprising (alkoxy) polyalkylene glycols, poly(alkyl) alkylene adipate diols, optionally hydrogenated, alpha -hydroxylated or alpha , omega -dihydroxylated polydienes, mono-or polyhydroxylated polyalkylene, polylactides containing hydroxy terminal functions, polyhydroxyalkanoates, polysaccharides or optionally modified simple sugars (mono- and oligosaccharides); a polymer comprising at least one thiol function, preferably alpha -thiol or alpha , omega -thiol polystyrene, alpha -thiol or alpha , omega -thiol polymethacrylate, and/or alpha -thiol or alpha , omega -thiol polybutadiene; or a co-oligomer or vinylic copolymer of family of acrylic, methacrylic, styrenic or dienic polymers, which is obtained from a co-polymerization of acrylic, methacrylic, styrenic or dienic monomers and functional monomer having either a hydroxyl group, a thiol group. The polymer containing at least one hydroxyl function is (methoxy) polyethylene glycol, polypropylene glycol, polytetramethylene glycol, poly (2-methyl-1,3-propylene adipate) diol, poly(1,4-butylene adipate)diol, alpha - omega -dihydroxylated polybutadiene, alpha - omega -dihydroxylated polyisoprene, mono-or polyhydroxylated polyisobutylene, poly (3-hydroxybutyrate), poly(3-hydroxyvalerate), starch, chitin, chitosan, dextran, cellulose, sucrose and/or isomaltulose. The molar ratio of cyclic monomer to the polymeric initiator is 5-500, preferably 40-100. EXAMPLE - Polyethylene glycol (number average molecular weight of 2000, 75 mg) and N-((trifluoromethyl) sulfonyl)-diphenylester phosphoramidic acid (34 mg) were added to a solution of epsilon -caprolactone (400 mu l) in toluene (3.6 ml). The reaction mixture was stirred under argon at 30 degrees C to obtain corresponding copolymer.