Spiropyrans have played a pivotal role in the emergence of the field of chromism following
their discovery in the early 20th century, with almost ubiquitous use in materials applications …

The last few years have seen an explosion of interest in traditional photochromic systems
not only for their applications in variable transmission devices, which continues to attract …

Spiropyrans undergo Cspiro–O bond breaking to their ring-open protonated E-merocyanine
form upon protonation and irradiation via an intermediate protonated Z-merocyanine isomer …

Spirobenzopyrans, which are well known as photochromic compounds, exist as
thermodynamically stable protonated ring-opened isomers (protonated merocyanine form …

Synthesis of spiropyrans exhibiting ring-opening/closing isomerization driven by external
stimuli is a challenging subject for the development of molecular sensors. A napthalimide …

Synthesis methods have been developed, and new spiropyrans of the benzophenazine
series have been obtained. In solution, all of the new compounds appear as semipermanent …

Merocyanine (MC) isomers that are formed after absorption of a UV photon by 1 ', 3 '-dihydro-
1 ', 3 '-3 '-trimethyl-6-nitrospiro [2 H-1-benzopyran-2 ', 2 '-(2 H)-indole] were studied. Several …

Design of spiropyrans showing spontaneous isomerization driven by the polarity of solvents
is an important consideration for the synthesis of optical sensory materials. Although some …

We report the first ultrafast ring closure kinetics of the merocyanine (MC) of a reverse
photochromic spiropyran 1 ', 3 ', 3 '-trimethyl-6, 8-dinitrospiro [2H-1-benzopyran-2, 2 …

Photochromism of spiropyrans has attracted much attention due to its potential in many light-
controlled system applications. However, several fundamental aspects regarding the …