Abstract: A photochromic compound is provided, which may be a pyran, an oxazine, or a fulgide. The photochromic compound has at least one substituent Q attached thereto, each Q independently being —N3, —CN, —COOR?, —CCR?, —C(R?)C(R?)R?, —OCOR?, —OCOOR?, —SR?, —OSO2R??, and/or —CON(R?)R?, wherein each R? is hydrogen, an unsubstituted or substituted alkyl group having from 1 to 18 carbon atoms; an unsubstituted or substituted aryl group, an unsubstituted or substituted alkene or alkyne group having from 2 to 18 carbon atoms, wherein the substituents are halo or hydroxyl and R?? is —CF3 or a perfluorinated alkyl group having from 2 to 18 carbon atoms. The number, locations and nature of the constituents Q are dependent upon the structure of the photochromic compound.

Abstract: A photochromic compound is provided, which may be a pyran, an oxazine, or a fulgide. The photochromic compound has at least one substituent Q attached thereto, each Q independently being —N3, —CN, —COOR?, —CCR?, —C(R?)C(R?)R?, —OCOR?, —OCOOR?, —SR?, —OSO2R??, and/or —CON(R?)R?, wherein each R? is hydrogen, an unsubstituted or substituted alkyl group having from 1 to 18 carbon atoms; an unsubstituted or substituted aryl group, an unsubstituted or substituted alkene or alkyne group having from 2 to 18 carbon atoms, wherein the substituents are halo or hydroxyl and R?? is —CF3 or a perfluorinated alkyl group having from 2 to 18 carbon atoms. The number, locations and nature of the constituents Q are dependent upon the structure of the photochromic compound.

Abstract: A thrust vector actuation control system and method is configured to allow self-testing of the entire actuation system and/or its individual system components. The control system also provides real-time, continuous monitoring of actuation system status, and allows system gain and compensation parameters to be changed during vehicle operation remote from its launch site.