The composition of the present invention is a mixed composition including at least one metal compound (G) selected from a metal compound represented by the following formula (G1) and a condensate thereof, a polysilazane (F), and a compound (H) including a siloxane chain. M(R.sup.g10).sub.r(A.sup.g1).sub.m-r (G1) wherein M represents Al, Fe, In, Ge, Hf, Si, Ti, Sn, Zr, or Ta, R.sup.g10 represents a hydrocarbon chain-containing group or a hydrogen atom, r is 0 or 1, a plurality of A.sup.g1 each independently represent a hydrolyzable group, and m is an integer of 3 to 5 in accordance with the metal atom M.

The composition of the present invention is a mixed composition including at least one metal compound (G) selected from a metal compound represented by the following formula (G1) and a condensate thereof, a polysilazane (F), and a compound (H) including a siloxane chain. M(R.sup.g10).sub.r(A.sup.g1).sub.m-r (G1) wherein M represents Al, Fe, In, Ge, Hf, Si, Ti, Sn, Zr, or Ta, R.sup.g10 represents a hydrocarbon chain-containing group or a hydrogen atom, r is 0 or 1, a plurality of A.sup.g1 each independently represent a hydrolyzable group, and m is an integer of 3 to 5 in accordance with the metal atom M.

A mixed composition containing an organosilicon compound (A) and a silicon compound (B), wherein the organosilicon compound (A) is an organosilicon compound in which at least one trialkylsilyl group-containing molecular chain and at least one hydrolyzable group are bonded to a silicon atom, the silicon compound (B) is one or more silicon compounds selected from the group consisting of a silicon compound (b) represented by the following formula (b) and a condensate (bb) thereof, and in a chromatogram obtained by GPC chromatography of the mixed composition, a weight average molecular weight Mw in terms of standard polystyrene of a compound derived from at least one of the organosilicon compound (A) and the silicon compound (B) is 2000 to 12000,

Si(X).sub.p(OR.sup.b).sub.4−p  (b) wherein X is an alkyl group having 1 to 6 carbon atoms or a hydrogen atom, R.sup.b is an alkyl group having 1 to 6 carbon atoms, and p is an integer of 0 to 3.

A mixed composition containing an organosilicon compound (A) and a silicon compound (B), wherein the organosilicon compound (A) is an organosilicon compound in which at least one trialkylsilyl group-containing molecular chain and at least one hydrolyzable group are bonded to a silicon atom, the silicon compound (B) is one or more silicon compounds selected from the group consisting of a silicon compound (b) represented by the following formula (b) and a condensate (bb) thereof, and in a chromatogram obtained by GPC chromatography of the mixed composition, a weight average molecular weight Mw in terms of standard polystyrene of a compound derived from at least one of the organosilicon compound (A) and the silicon compound (B) is 2000 to 12000,

Si(X).sub.p(OR.sup.b).sub.4−p  (b) wherein X is an alkyl group having 1 to 6 carbon atoms or a hydrogen atom, R.sup.b is an alkyl group having 1 to 6 carbon atoms, and p is an integer of 0 to 3.

A method for producing a polycarbonate copolymer which has siloxane constituent units represented by any of formulae (1-1) to (1-4) and prescribed polycarbonate constituent units, the method having a polymerization step for polymerizing a silane-based compound selected from among a prescribed diaryloxysilane compound, a prescribed dialkoxysilane compound and a prescribed silicon compound, a carbonate compound and a diol compound such as an aromatic diol compound or an alicyclic diol compound in the presence of a transesterification catalyst. The polymerization step is carried out in a molten state under reduced pressure while removing alcohols derived from the carbonate compound.

##STR00001##

An energy-sensitive composition that yields a cured product with excellent crack resistance, a cured product of the composition, and a method of forming a cured product. The energy-sensitive composition includes a polysilane and a thermal base generator, in which the thermal base generator includes a compound represented by the following formula (b1):

##STR00001##

in which R.sup.b1 and R.sup.b2 each independently represents a hydrogen atom, a halogen atom, a nitro group, an alkyl group, an aryl group, an arylalkyl group, or an alkoxy group, R.sup.b3 represents a hydrogen atom or an alkyl group; n1 and n2 each independently represent an integer of 0 or more and 4 or less; Z.sup.q+ represents a q-valent organic cation composed of a base having a pKa of greater than 15; and q represents an integer of 1 or more.

An energy-sensitive composition that yields a cured product with excellent crack resistance, a cured product of the composition, and a method of forming a cured product. The energy-sensitive composition includes a polysilane and a thermal base generator, in which the thermal base generator includes a compound represented by the following formula (b1):

##STR00001##

in which R.sup.b1 and R.sup.b2 each independently represents a hydrogen atom, a halogen atom, a nitro group, an alkyl group, an aryl group, an arylalkyl group, or an alkoxy group, R.sup.b3 represents a hydrogen atom or an alkyl group; n1 and n2 each independently represent an integer of 0 or more and 4 or less; Z.sup.q+ represents a q-valent organic cation composed of a base having a pKa of greater than 15; and q represents an integer of 1 or more.

An energy-sensitive composition that yields a cured product with excellent thermal resistance and crack resistance, a cured product of the composition, and a method of forming a cured product. The energy-sensitive composition includes a polysilane and a thermal base generator, in which the thermal base generator includes an ionic compound and a nonionic compound. An anion moiety in the ionic compound preferably includes at least one of an anion having an oxaxanthone skeleton, an anion having a ketoprofen skeleton, and an anion having a fluorenone skeleton.

An energy-sensitive composition that yields a cured product with excellent thermal resistance and crack resistance, a cured product of the composition, and a method of forming a cured product. The energy-sensitive composition includes a polysilane and a thermal base generator, in which the thermal base generator includes an ionic compound and a nonionic compound. An anion moiety in the ionic compound preferably includes at least one of an anion having an oxaxanthone skeleton, an anion having a ketoprofen skeleton, and an anion having a fluorenone skeleton.

A resin composition including a silicon-containing resin component and a solvent, the silicon-containing resin component includes (I) mentioned below, the solvent including at least one of a terpene compound having at least one of a hydroxy group and an acetoxy group, and a cyclic skeleton-containing acetate compound (excluding the terpene compound): (I) a polysilane-polysiloxane resin having a polysilane structure and a polysiloxane structure.