Abstract: There is provided polysilarylene-polysiloxane copolymers comprising:(a) at least one unit of the formula ##STR1## (b) at least one unit of the formula ##STR2## and (c) at least one unit of the formula ##STR3## There are also provided curable compositions comprising the instant polymers and a cure initiator, articles having the instant compositions cured to a substrate, and methods for making the aforesaid copolymers, curable compositions and articles.

Abstract: There is provided a curable composition comprising:(A) an organopolysiloxane block copolymer comprising:(i) at least one siloxane block consisting essentially of from about 6 to about 120 units of the formula R.sub.2 SiO,(ii) at least one siloxane block consisting essentially of from about 3 to about 160 units of the formula R.sup.1 SiO.sub.1.5,(iii) optionally, at least one siloxane block consisting essentially of from 1 to about 80 units of the formula R.sup.2 SiO.sub.1.5, and(iv) at least one siloxane block consisting essentially of from about 0.1 to about 10 mole percent of the sum of (i), (ii) and (iii) of units of the formula RR.sup.3 SiO,where R is a C.sub.1-5 substituted or unsubstituted alkyl radical or a C.sub.6-10 substituted or unsubstituted aryl or alkaryl radical, R.sup.1 is a C.sub.6-10 substituted or unsubstituted aryl or alkaryl radical, R.sup.2 is a C.sub.1-5 substituted or unsubstituted alkyl radical and R.sup.3 is a C.sub.