| abstract |
Certain compounds within the general formula (I) n n n wherein: n Ra and Ra′ are independently alkyl, aryl or aralkyl; Rb and Rb′ are independently CH 2 , CH-alkyl, CH-aryl or CH-aralkyl; R 1 and R 2 , are independently selected from substituted or unsubstituted alkyl, aryl, aralkyl, heteroaryl, heteroaralkyl; and m is at least 1, and preferably fluorinated or cross-linkable under controlled conditions. n Compounds of formula (I) are reactable with silanediols to produce linear polycondensate organosiloxanes of defined structure without uncontrolled crosslinking. The polycondensates may be cured and are suitable as optical materials. |