Silicone-based working fluid composition

A silicone-based working fluid composition which comprises:

• (A) 100 parts by weight of a diorganopolysiloxane or a mixture of diorganopolysiloxanes each represented by the general formula
• R.sup.1 --SiR.sup.2.sub.2 -O).sub.m SiR.sup.2.sub.2 -R.sup.1,
• in which each R.sup.1 is trihydrocarbylsiloxy group or a hydroxy group independently from the other, R.sup.2 is an alkyl group or a phenyl group and m is a positive integer in the range from 20 to 2000, the groups denoted by R.sup.1 in the overall component (A) being a combination of trihydrocarbylsiloxy groups and hydroxy groups in such a molar proportion of the former to the latter in the range from 95/5 to 10/90, and
• (B) from 0.01 to 5 parts by weight of an organopolysiloxane represented by the general formula
• R.sup.3 --SiR.sup.2.sub.2 -O).sub.n SiR.sup.2 -R.sup.3
• or ##STR3## in which R.sup.2 has the same meaning as defined above, R.sup.3 is an imino-substituted phenoxy group selected from the class consisting of 4-anilinophenoxy group, 4-(4-anilino)anilinophenoxy group, 4-(.alpha.-naphthylamino)phenoxy group and 4-(.beta.-naphthylamino)phenoxy group, n is a positive integer in the range from 1 to 50, q is a positive integer in the range from 1 to 10 and p is zero or a positive integer with the proviso that p+q is in the range from 1 to 48.