Rachel S. Kohn

Naphthalocyanine chromophores for WORM-type optical data storage media

Hoechst Celaneses proprietary naphthalocyanine record-ing layer materials exhibit excellent performance for a write-once read many (WORM) optical data storage media. This pit-forming medium shows a CNR greater than 50 dB and a bit error rate less than 1 x 10 for data recorded at either 780 or 830 nm. The stability under accelerated aging conditions is superior to that for coririercial media.

Dynamic Laser Marking Experiments On An Organic Optical Storage Medium

Dynamic GaAlAs diode laser marking experiments on an optical data storage medium are reported. The medium comprises thin films of a proprietary organic recording layer that are spin coated onto both glass and plastic disk substrates. These amorphous films with high substrate incident reflectivities (R - 30%) are stable to both air and moisture. Writing experiments were performed in the substrate incident mode. Readable marks were made with 2 to 15mW of laser power at pulse widths down to 50 ns. The marks are pits with well-defined rims. The dependence of laser recording quality on both disk and marking parameters will be discussed.

Accelerated Aging Studies for Organic Optical Data Storage Media

The excellent stability of Hoechst Celanese WORM media was demonstrated in accelerated aging studies. CNR data was measured as a function of exposure time for disks exposed to 65°/80% RH, 80°/80% RH, and 90°/80% RH. Disks were also exposed to a high intensity xenon lamp to compare the relative stability to visible and ultraviolet radiation. The stability of the polycarbonate substrate and the recording layer were investigated.