Barry Van Gemert

Photochromism of Diarylnaphthopyrans

A series of 3,3-diaryl-3H-naphtho[2,1-b]pyrans were prepared and their photochromic properties measured in plastic matrix. The influence of a variety of substituents on color, intensity, and fade were studied.

Naphthopyrans. Structural Features and Photochromic Properties

Abstract Structural modifications to photochromic 3H-naphtho[2,1 -b]pyrans and 2H-naphtho[1,2-b]pyrans have produced compounds that have found utility in plastic ophthalmic lens applications. The influence of substituents on color, optical density, and fade rate are reported. Synthetic routes to products and key intermediates are also outlined.

The commercialization of plastic photochromic lenses : A tribute to John Crano

Abstract With 1999 marking the 100th anniversary of the discovery of organic photochromic compounds1, it is a fitting time to reflect back on commercial uses that have developed from this interesting class of organic compounds over the years. From the many applications that have been proposed, including security devices and optical memory storage, the one application that has achieved substantial commercial success is switchable lenses. Such lenses, based on inorganic photochromes (AgX), have been available since the mid 1960s, but it is only in the last 10 years that organic systems with acceptable performance have been available in the marketplace. From the mid 1980s until his sudden death in early 1998, John Crano lead the research effort at PPG Industries that developed the photochromic systems that have been commercialized by Transitions Optical Inc. under the name Transitions®.

Color Tunability in Photochromic Naphthopyrans

Abstract Photochromic naphthopyrans are of particular interest due to their wide use in applications such as switchable eyewear, security devices and novelty items. The spectral properties of the activated form are important in many of these applications. This paper reports the effect of substituents on the visible absorption of the activated form(s). In addition to color, other photochromic properties of naphthopyrans are briefly discussed.