Comparative Study of Coumarin-120 (C-120) and Stilbine-3 (STB-3) Laser Dyes Doped in Sol-Gel Glasses

In 1967 the first work in solid state dye laser was performed by doping rhodamine dyes in Polymethylmethacrylate (PMMA) materials. Since then some materials like various types of polymers, co-polymers, poly composite glasses have been used as host matrices for doping different laser dyes. Polymers suffer from limited mechanical and thermal stability. Hence glasses can be the alternative hosts. However, because of high processing temperature leading to permanent destruction of dye molecules, the conventional glass preparation technique is not suitable for the introduction of organic laser dyes. This difficulty can be overcome by introducing the laser dye molecules in sol-gel glass which is prepared at low temperature. Recent work with sol-gel glasses shows that these glasses may prove to be better materials compared to polymeric materials because glasses being hard, best optically transparency in Near UV-UV and Visible region and show better photostability. In this research work we reported, comparative study of the photophysical properties of Coumarin-120 (C-120) belonging to 7-aminocoumarin family having two hydrogen atoms attached to the N atom at the 7-position, with Stilbene-3 (STB-3) in three types of HCl catalyzed SiO2 sol-gel matrices prepared by Method I, Method II and Method III respectively.

C-90和C-120盒式带带基与磁层厚度选择的计算方法

C-90和 C-120盒式录音磁带,由于其长度比通用的 C-60盒式带分别增加了1/2和1倍之多,所以带饼的直径也随之增大。生产时如果不适当地选择带基厚度和有效地控制磁层的厚度,那么就会造成磁带总厚度过大,导致带饼转动力矩加大,使走带不畅,甚至走不动,或因带基厚、磁层薄而降低电性能;或因带基薄而磁带机械强度差,使磁带易拉伸变形。因此,对生产厂家来说,选择好带基厚度。