Homo- and copolycarbonates of spirobiindane bisphenols are prepared by first reacting phosgene with a substantially pure spirobiindane bisphenol in the presence of aqueous base in a heterogeneous medium at a pH in the range of about 9-11, and subsequently adding an interfacial polycarbonate formation catalyst and, optionally, a dihy­droxyaromatic compound and a chain termination agent and continuing phosgene passage at a pH of at least about 10. By this method, there may be prepared homo- and copolycar­bonates of 6,6'-dihydroxy-3,3,3',3'-tetramethyl-1,1-spiro­(bis)indane having high molecular weight. Said homopoly­carbonates and copolycarbonates with bisphenol A may be used for manufacture of optical disks having low birefringence.