Described are spirobenzoxazine pyrrolo pyridine compounds. Also described is the use of such compounds as photochromic substances in organic host materials such as an organic transparent plastic material, e.g., an ophthalmic lens, to impart a photochromic response thereto.
A spiro (indolino) oxazine compound of general formula (I) ##STR1## wherein R.sub.1 represents a group of the formula --NR.sub.2 R.sub.3 wherein each of R.sub.2 and R.sub.3, which may be the same or different, independently represents an alkyl group, or a carbocyclic group, preferably aryl, or a heterocyclic group, or R.sub.2 and R.sub.3 taken together with the nitrogen atom to which they are attached represent a heterocyclic ring having one or more heteroatoms and which may optionally carry at least one substituent selected from alkyl, aryl or heteroaryl groups; --X-- is selected from --O--, --S--, --Se--, --NH-- or --NR-- wherein R represents an alkyl group, and ring A is a carbocyclic or heterocyclic ring which can be optionally substituted with a group of formula R.sub.8 as defined above, or may optionally have a carbocyclic or heterocyclic ring fused thereto; and wherein R.sub.4 -R.sub.8 are as defined in the specification. The spiro (indolino) oxazine compounds of the invention are useful as photochromic materials.
Disclosed is a novel spirooxazine compound having excellent durability which changes into a colored form upon irradiation with the light containing ultraviolet rays such as of sunrays or the light from a mercury lamp, the change being reversible.
The new photochromic compounds of the invention have the formula of a indolino-spiro-oxazine comprising an indolinic part and an oxazine part wherein the oxanine part comprises an unsaturated 6-atoms bi-aza heterocycle of the pyrimidine type included in a nucleus of the quinazoline part. Preferred photochromic compounds are those showing the following developed formula (II) wherein R.sub.1 is a methyl or isopropyl group R.sub.2 and R.sub.3 are methyl groups R.sub.4 is H or --OCH.sub.3 ##STR1##
A naphthopyran compound of general formula (I) ##STR1## wherein R.sub.1 represents an alkyl group or an aryl group; each of R.sub.4 and R.sub.5, which may be the same or different, independently represents an alkyl, alkenyl, carbocyclic or heterocyclic group, or R.sub.4 and R.sub.5 taken together with the carbon atom to which they are attached form a carbocyclic ring or a heterocyclic ring; and R.sub.6 represents a hydrogen atom or a substituent selected from alkyl, alkoxy, aryl, aryloxy, heteroaryl, halogen, amino, substituted amino, azo, imino, amide, carboxylate, ester, cyano, trifluromethyl or nitro, and in addition R.sub.6 may represent a carbocyciic or heterocyclic ring fused to ring A. The naphthopyran compounds of the invention are useful as photochromic materials in lenses, e.g. sunglasses, and photochromic transparencies for cars and aircraft.
A process for incorporating by thermal diffusion a photochromic substance into a synthetic organic host material is described. In the process, a surface of the host material containing a coating of a resin composition of from about 5 to about 50 parts of hydroxy (C.sub.2 -C.sub.3) alkyl cellulose, e.g., hydroxy propyl cellulose, and from about 95 to about 50 parts of poly(vinylpyrrolidone), which resin composition contains a photochromic substance, is heated to diffuse at least a portion of the photochromic substance into the surface of the host material. Subsequently, the coating is removed by washing with warm soapy water. In a particular embodiment, the host material is a polymer prepared from diethylene glycol bis(allyl carbonate).
