As the first movement's Allegro molto moderato begins alternate major and minor chords and modes dizzyingly, a few bars for each at a time, and the movement becomes more stable only with the introduction of the main lyrical theme at bar fourteen. The first movement is riddled with tremolandi, which also lead into the repeat of the exposition, and contains several other new departures for the composer. This may include the use of a motive in triplets to connect the first and second main groups of this sonata form; the second group opens, exactly as happens in the later-written String Quintet and similar to the technique in some works by Beethoven — not in the dominant key but with a quiet theme in the mediant, B-flat, with rhythm not quite the same as that of the lyrical theme that slowed matters down early on, and with pizzicato accompaniment. There is a triplet-dominated, agitated transition and the same theme is heard, now in D, with triplet accompaniments; the triplets, not the theme, continue to the end of the exposition, and descend gradually from D down to G major for the repeat, or for the second ending and the beginning of the development, where continuity means the continued rustling of quiet strings, building for a bit by exchanging with more energetic passages, then bringing in faster versions of the dotted rhythms of the main themes. The climax of the development leads to a particularly quiet recapitulation, much varied at its opening from what we had heard originally. In the coda the opening of the quartet, both its rhythm and its major/minor exchanges, get a further chance to play themselves out. There is a remarkably innovative harmonic passage in the first movement. Between mm. 414 and 429 Schubert prolongs G major with an equal subdivision of the octave using major 3rds. Passing seventh chords in the bass provide a smooth linear progression connecting these major thirds, the result of which is a descent in whole tones in the bass-voice cello. The following major 3rd prolongations occur: G E-flat B G E-flat. In measure 426 Schubert enharmonically reinterprets this dominant-seventh structure, resolving it as a German augmented 6th, thus proceeding bVI-V-I in mm. 427-429.
II. Andante un poco moto
The dramatic slow movement contains much in the way of march rhythm and sudden upward violin glides followed by drops to the lowest string, and again much use of tremolo.
III. Scherzo: Allegro vivace with trio: Allegretto
The scherzo is light-textured, fleet for much of its span, foreshadowing those of Mendelssohn. The scherzo’s trio is a mild accompanied duet, first between cello and first violin, then first violin and viola, then again cello and first violin.
IV. Allegro assai
The finale continues the preoccupation of the first movement in an extended and ambiguous movement that might be sonata or rondo, might be G major or minor. The opening theme is more extreme, more rapid, in its exchanges of major and minor chords than was that of the first movement; its rhythms are reminiscent of tarantella, as with that of the previous quartet — which the movement resembles but only in some ways, and the movement has a capricious quality. The quartet was first published no later than 1852, by Diabelli of Vienna.
Cultural legacy
In Woody Allen's 1989 comedy-drama Crimes and Misdemeanors, parts of the Allegro molto moderato are used as a dramatic measure during several scenes that form central parts of the 'crimes' plot. In Gramophone, Stephen Johnson referred to the work as Schubert's greatest string quartet, and speculated that it is heard less frequently than the composer's previous two quartets not because of lower quality but because it is less accessible.
Recordings
Schubert's String Quartet No. 15 in G major has been recorded by many quartets, including:
