Prokofiev's G Minor Quintet and Toch's "Tanz-Suite" share several characteristics, an insouciance and a sense of humor chief among them. They are both large, significant works couched in a lighthearted guise, and they framed two pieces of very different provenances and persuasions in the program that the Theater Chamber Players of Kennedy Center brought to the Library of Congress last night.

The first was the premiere of a fine new piece by Daria Semegen called simply Music for Violin and Piano. A series of contempletive tone paintings, it evolves from the abstract to the romantic, the textures always clear and the tempos always deliberate. Semegen handles sonorities with great imagination and an ear for details, and violinist Hamao Fujiwara and pianist Dina Koston played it beautifully. Koston, in particular, has unusual control over attack and touch on the keyboard, and this is a piece to challenge every ounce of her special skills.

The Mozart Oboe Quartet was the other piece on the program, in this company, perhaps, more cherished for its gentleness and repose than for its sophistication. Oboist Rudolph Vrbsky gave an agile reading, and his collaborators, violist Masao Kawasaki, cellist Evelyn Elsing and Fujiwara, chose roles as accompanists rather than as partners.