The invention relates to a copolyamide comprising at least two different units corresponding to the following general formulation: A/X.T A is chosen from a unit obtained from an amino acid, a unit obtained from a lactam and a unit corresponding to the formula (Ca diamine).(Cb diacid), with a representing the number of carbon atoms of the diamine and b representing the number of carbon atoms of the diacid, a and b each being between 4 and 36, advantageously between 9 and 18, X.T denotes a unit obtained from the polycondensation of a Cx diamine and of terephthalic acid, with x representing the number of carbon atoms of the Cx diamine, x being between 9 and 36, advantageously between 10 and 18, characterized in that said copolyamide exhibits: a content of amine chain ends of greater than or equal to 20 μeq/g, a content of acid chain ends of less than or equal to 100 μeq/g, and a content of unreactive chain ends of greater than or equal to 20 μeq/g, and to the process for the preparation of said copolyamide, to a composition comprising this copolyamide and to the use of this copolyamide and of such a composition.