Abstract: Organosilicon grease-like compounds having good shear stability and being suitable for optical coupling are prepared by mixing a phenylmethylpolysiloxane fluid or a trimethylsiloxy endblocked fluid consisting of decylmethylsiloxane, tetradecylmethylsiloxane and alpha-methylstyrenemethylsiloxane units, a finely divided silica, and a polyalkylene oxide. A typical compound would be a mixture of 150 parts of a phenylmethylpolysiloxane, 15.5 parts of a fume silica having surface area of 380 square meters per gram, and 4 parts of polypropylene oxide having a molecular weight of 2,000. Such a compound has a light transmission in excess of 80% and excellent work shear stability.