PPG Industries has agreed to sell its 51% interest in Transitions Optical, a maker of photochromic lenses, to its partner, optics specialist Essilor, for $1.7 billion. The deal, expected to close early in 2014, will be PPG’s third major restructuring move in less than a year. The company merged its chlor-alkali unit with Georgia Gulf to form Axiall and purchased AkzoNobel’s North American architectural coatings business. Transitions Optical had sales of $800 million in 2012. PPG will continue to supply optical dyes and provide R&D services for the business.