| 摘要 |
Polydiorganosiloxane polycarbonate block copolymers which have a mean molecular weight Mw (weight average) of from 8,000 to 30,000, and contain from 90 to 99.9 % by weight of aromatic carbonate structural units and from 10 to 0.1 % by weight of polydiorganosiloxane structural units having a degree of polymerisation of from 2 to 40, are used as substrates for optical data stores (memories). |
