Preparation and photochromic performance characteristics of polyester-naphthopyran conjugates in a rigid host matrix

Telechelic naphthopyran functionalized polyester conjugates have been synthesized through the use of polyester diols, namely polycaprolactone diol and poly(diethylene glycol adipate). These low Tg polymeric materials provide a soft and mobile environment to the naphthopyran photochromic dye when incorporated within a rigid thermoset polymeric matrix, which is evidenced by increased fade performance characteristics compared with the non-conjugated control dye. The t1/2 fade speeds were reduced by between 51 and 58%, whilst the t3/4 fade speeds were reduced by between 68 and 74% for the conjugates tested. The fade speed enhancement was dependent on the molecular weight of the conjugated polyester, which can allow for the tuning of fade speed within the host matrix.

Figure optionsDownload as PowerPoint slideHighlights▶ Telechelic photochromic naphthopyran-polyester conjugates were synthesized. ▶ Conjugates showed fast decolouration kinetics when incorporated in a rigid matrix. ▶ Fade speed is dependent on polyester molecular weight, allowing tuning.