Photochromic compounds, a process for their preparation, and their use

A compound of the formula I ##STR22## in which X is O, S, SO, SO.sub.2 or NR.sub.13,

• R.sub.1 to R.sub.5, independently of one another, are H, C.sub.1 -C .sub.12 alkyl, C.sub.1 -C.sub.12 alkoxy, C.sub.1 -C.sub.12 alkylthio, C.sub.1 -C.sub.4 alkyl--SO--, C.sub.1 -C.sub.4 alkyl--SO.sub.2 --, halogen, CF.sub.3, --CN, --NO.sub.2, --OH, --COOR.sub.14, --CON(R.sub.15).sub.2, or --N(R.sub.15).sub.2, or the radical of the formula ##STR23## in which R.sub.16 and R.sub.17, independently of one another, are C.sub.1 -C.sub.6 alkyl, phenyl, C.sub.1 -C.sub.6 alkylphenyl or (C.sub.1 -C.sub.6 alkyl).sub.2 -phenyl, or R.sub.3 and R.sub.4 or R.sub.4 and R.sub.5, in each case together, are --CH.dbd.CH--CH.dbd.CH--, R.sub.6 to R.sub.12, independently of one another, are H, C.sub.1 -C.sub.12 alkyl, C.sub.1 -C.sub.12 alkoxy, C.sub.1 -C.sub.12 alkylthio, C.sub.1 -C.sub.12 alkyl--SO--, C.sub.1 -C.sub.12 alkyl--SO.sub.2 --, benzyl or C.sub.1 -C.sub.46 alk-1-yl which is 1-substituted by a total of one or two --CN and/or --COOR.sub.14, phenyl, phenyl--C.sub.1 -C.sub.4 alkylene, phenyl--CO--, phenyloxy, phenylthio, phenyl--SO--, pnenyl--SO.sub.2 --, benzyloxy, benzylthio, benzyl--SO--, benzyl--SO.sub.2 --, C.sub.1 -C.sub.18 acyl--O--, --COOR.sub.14, --CON(R.sub.15).sub.2, C.sub.1 -C.sub.18 acyl--NR.sub.15 --, (R.sub. 15).sub.2 N--, halogen, --CF.sub.3 or --CN, or each two adjacent racicals of R.sub.6 to R.sub.12 are the groups --CO--O--CO-- or --CO--NR.sub.13 --CO-- the pheynyl radicals and radicals containing pnehyl groups being unsubstituted or substituted by halogen, --CN, --CF.sub.3, C.sub.1 -C.sub.6 alkylthio, C.sub.1 -C.sub.6 alkoxy, C.sub.1 -C.sub.6 alkyl, --COOR.sub.14, --CO--N(R.sub.15).sub.2 or C.sub.1 -C.sub.12 acyl--O--,
• R.sub.13 is H, C.sub.1 -C.sub.12 alkyl or C.sub.1 -C.sub.12 acyl, phenyl or benzyl, which are unsubstituted or substituted by C.sub.1 -C.sub.6 alkyl, C.sub.1 -C.sub.6 alkoxy, C.sub.1 -C.sub.6 alkylthio, halogen or --COOR.sub.14,
• the two R.sub.15 together are C.sub.4 -C.sub.8 alkylene, 3-oxa-1,5-pentylene, 3-thia-1,5-pentylene, 1.3-butadiene-1,4-diyl or 2-aza-1,3-butadiene-1,4-diyl, or the R.sub.15 radicals, independently of one another, are H, C.sub.1 -C.sub.12 alkyl, or phenyl or benzyl which is unsubstituted or substituted by C.sub.1 -C.sub.6 alkyl, C.sub.1 -C.sub.6 alkoxy, C.sub.1 -C.sub.6 alkylthio, halogen or --COOR.sub.14, and
• R.sub.14 is phenyl, (C.sub.1 -C.sub.4 alkyl)phenyl, benzyl, 1-phenyleth-2-yl, benzyl or 1-phenyleth-2-yl substituted by 1 or 2 C.sub.1 -C.sub.12 -alkyl, C.sub.1 -C.sub.20 -alkyl, C.sub.3 -C.sub.8 -cycloalkyl, C.sub.3 -C.sub.8 -cycloalkylmethyl, or a polyoxaalkylene radical of the formula --(C.sub.n H.sub.n2 --O--).sub.m R.sub.18, in which n is an integer from 2 to 4, m is a number from 1 to 12, and R.sub.18 is C.sub.1 -C.sub.18 -alkyl, C.sub.34 -C.sub.8 -cycloalkyl, C.sub.5 - or C.sub.6 -cycloalkylmethyl, phenyl, benzyl, or phenyl or benzyl, substituted by 1 or 2 alkyl groups having 1 to 12 carbon atoms, with the exception of 1-phenoxy-4-methylxanthen-9-one.