A ring-opened copolymer composition comprising a ring-opened copolymer containing structural unit derived from a norbornene compound represented by general formula (1) below and structural unit derived from a monocyclic olefin, wherein a content of a norbornene compound represented by general formula (1) is 1 ppm by weight or more and 1000 ppm by weight or less based on the ring-opened copolymer is provided.

##STR00001## wherein R.sup.1 to R.sup.4 are each a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms, or a substituent containing a halogen atom, a silicon atom, an oxygen atom or a nitrogen atom, and R.sup.2 and R.sup.3 may be bonded to each other to form a ring, and “m” is 0 or 1.

Phenoxyimine-based complexes, when activated, are suitable for catalyzing ring-opening metathesis polymerization (ROMP) reactions of cyclopentene and a comonomer under mild reaction conditions, for example, at reaction temperatures of about 196 C. and about 70 C. in diluents like toluene. The use of such activated phenoxyimine-based complexes may favor polymer products with a high cis-content.

A crosslinked rubber is a member for use in an environment at 10 C. or less produced by crosslinking a polymer composition containing 20 to 200 parts by weight of carbon black with respect to 100 parts by weight of a rubber component containing a monocyclic olefin ring-opening polymer having a proportion of cis bond of a structural unit derived from a monocyclic olefin of 45 to 95%.

A liquid cyclopentene ring-opened polymer having a weight average molecular weight (Mw) of 1,000 to 50,000 and a cis double content of 55% or more in repeating units.

A liquid cyclopentene ring-opened copolymer includes a monomer unit derived from cyclopentene and a monomer unit derived from a norbornene compound, the monomer unit derived from cyclopentene being present in an amount of 60 to 95 wt %, the liquid cyclopentene ring-opened copolymer having a hydroxyl group-terminated copolymer chain and having a melt viscosity at 25 C. of less than 500 Pa.Math.s, which is measured using a B-type viscometer.

A crosslinked rubber is a member for use in an environment at 10 C. or less produced by crosslinking a polymer composition containing 20 to 200 parts by weight of carbon black with respect to 100 parts by weight of a rubber component containing a monocyclic olefin ring-opening polymer having a proportion of cis bond of a structural unit derived from a monocyclic olefin of 45 to 95%.

A ring-opened copolymer including structural units derived from a norbornene compound having a specific structure and structural units derived from a monocyclic olefin, wherein the proportion of the structural units derived from a norbornene compound is 25 to 90 wt % and the proportion of the structural units derived from a monocyclic olefin is 10 to 75 wt % relative to the total repeating structural units in the ring-opened copolymer, the weight average molecular weight of the ring-opened copolymer is 100,000 to 1,000,000, and the cis/trans ratio of the ring-opened copolymer is 0/100 to 50/50.

The invention relates to conducting and semi-conducting photoreactive compounds, represented by the general formula (I), to the use of these compounds for the preparation of oriented and/or orientation layers; and to their use in the construction of unstructured and structured optical, electro optical or optoelectronic elements and multi-layer systems.