Importance

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Abstract

An azaindoline spiro-oxazine of the general formula (I): ##STR1## wherein R.sub.1 represents an aliphatic or aromatic group; each of R.sub.2 and R.sub.3 independently represents a hydrogen atom, an aliphatic or aromatic group or an alkoxy group, or R.sub.2 and R.sub.3 together with the carbon atom to which they are attached represent an alicyclic group; R.sub.4 represents a hydrogen atom or an aliphatic or aromatic group; ring A contains one or more nitrogen atoms in the ring and may be unsubstituted or substituted provided that there is no substituent on any nitrogen atom in the ring; and ring B may be unsubstituted or substituted by at least one substituent provided that the 6'-position in ring B is not substituted by an amine function or hydroxyl group. The spiro-oxazine compounds are useful for imparting photochromic properties to a plastics host material such as a plastics lens.

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First Claim