Massachusetts' highest court has declared that the state's new law permitting voluntary morning prayer in public school classrooms is unconstitutional.

The full Supreme Judicial Court said that the statute, which went into effect Feb. 4, violated the Constitution's required separation of church and state. It said there was no question that the prayer sessions were "religious in character, for prayer is an invocation to the Diety."

The law required teachers to ask for student volunteers to lead school classes in prayer. It also permitted students who did not wish to participate to leave the classroom.

Some school districts began requiring teachers to request the prayers as soon as the law went into effect; others refused to until the courts ruled on the law's constitutionality although state school officials threatened to take action to force compliance.

The new law was challenged by the Civil Liberties Union of Massachusetts on behalf of parents living in the Farmingham and Marblehead shcool districts.

In 1956, Massachusetts prescribed a moment of silence for personal prayer or meditation in its public schools. The measure was upheld 10 years later by a three-judge federal panel because it provided reasonable options for students who chose not to pray.

Meanwhile, a similar bill permitting student volunteers to lead prayer at the start of assemblies in public school has been approved by the Arizona House of Representatives.

The measure, which also provides that students who object may be excused, now goes before the Arizona Senate, where it is expected to pass.